Before I get into the meat of this post, I first want to wish everyone here in the United States (US) a very Happy Thanksgiving this week.

I am wishing you a harvest of blessings, good health, good times and something for which you can be grateful every single day of your life.

And next, this will in all likelihood be the last scrapbooking tip for 2024. The Holiday Season here in the US has nearly begun. And if you’ve been following me since before December of last year, you know how I handled things in 2023.

Rather than putting out tips during a time when people already have so much on their plates, I’d rather continue last year’s trend of just posting some reflective thoughts on navigating the remainder of the year. With that said, I hope you enjoy this last tip and can find a way to work toward a calm, blessed and festive December.

Now, on to Adjustment Layers…

In my “More Glowing” post from last week I used some Photoshop Elements (PSE) Adjustment Layers to create the glowing antler effect. How many other Adjustment Layers do you use or even know about?

If you’re really not exactly sure what an Adjustment Layer is, you can think of it as a sort of “veil” coloring/modifying the underlying layer(s) in a non-destructive way.

Some of the Adjustment Layers in PSE have names that resemble some PSE Filters (i.e., Posterize, Threshold, Gradient Map) and you may be wondering what the difference is between a Filter and an Adjustment Layer is.

Adjustment Layers allow you to make non-destructive edits to your image by applying various adjustments without permanently altering the image’s pixels.

Filters permanently modify the appearance of an image by adding effects like artistic styles, blur, or sharpening, generally affecting only the active layer or selection, irrevocably altering the pixels to which they are applied.

Essentially, Adjustment Layers are non-destructive and provide more flexibility to edit and refine adjustments later, while Filters are permanent and generally used for very specific visual effects.

Using Adjustment Layers

I very briefly answered the questions posed in the intro above. But I am going to provide more detailed answers for each of those questions.

Quick refresher before I do that. I use PSE – 2024. So, my screen shots may look different than what you see on your screen.

Creating Adjustment Layers

Even if you read last week’s post about the glowing antlers, this section may still be worth a quick read as I’ll cover some things that weren’t discussed last week. If you feel comfortable with creating Adjustment Layers feel free to skip ahead.

So, how do you make an Adjustment Layer? There are actually two ways that I can create an Adjustment Layer in PSE.

Via The Tool Bar

As I showed you last week, the first way is to go up to the main tool bar and click Layer->New Adjustment Layer:

When I select the type of adjustment I want to create, PSE will open the New Layer dialog box with a default “Name” set to the name of the adjustment I have selected. I selected Brightness/Contrast so this is how my dialog box popped up:

The number in this default name can vary depending on whether or not I have any other adjustments of the same type already in my file. This is my first Adjustment Layer which is why the number is 1. You can rename the layer any way you wish.

Now, if you read last week’s post you already know about the check box directly below the Name field. If I had more than one layer in this file and only wanted the adjustment applied to the “active” layer, I would check that “Use Previous Layer to Create Clipping Mask” box. This tells PSE to immediately clip this Adjustment Layer to the layer directly below.

I don’t have any other (non-blank) layers so I don’t need to check that box. And I’m fine with all the other default settings so I click OK to confirm.

Via The Layers Panel

The second way to create an Adjustment Layer is to go to the top of the Layers Panel and click on the “half-moon” icon:

There are two significant differences if I use this the “half-moon” option to create an Adjustment Layer.

When I click that icon, I get a completely different drop down than the one you saw in the first option above:

Notice the first three options here; Solid Color, Gradient, Pattern? I don’t see those when I create an Adjustment Layer by going up to the main tool bar and clicking Layer->New Adjustment Layer.

The first three options in the dropdown above are actually for creating a “Fill Layer” NOT an Adjustment Layer. And I’m not talking about Fill Layers today so I’m just going to ignore those options for now.

Now for the other difference with this method. When I select the type of adjustment I want to create, PSE does NOT open the New Layer dialog box as it did in the first option above. PSE just automatically creates the Adjustment Layer with a “default” name and I won’t have the ability to check that “Use Previous Layer to Create Clipping Mask” box.

So, there’s one thing to consider before you decide which method to use when creating an Adjustment Layer…do you want to apply this adjustment to only one layer in your file?

Shhhh…a little secret here. It’s not a big deal if you can’t or forget to “check that box” using the first option. There are other ways to handle clipping the Adjustment Layer manually.

Moving on with the remaining questions posed at the beginning of this post…

What Are Adjustment Layers

As I already mentioned, in PSE, Adjustment Layers allow you to make non-destructive edits to your image by applying brightness, contrast, color and other adjustments without permanently altering the pixels of the image.

By default, an Adjustment Layer affects all layers below it, although you can change this easily.

When you create an adjustment layer, the Layers Panel displays a white box (Mask) representing the adjustment for that layer. This mask provides you the capability to alter what is or isn’t affected by the adjustment.

Adjustments Layer Benefits

Again, Adjustment Layers allow for non-destructive edits to an image while Filters directly alter the pixels in a selected area of the image by permanently changing the image data.

Adjustment Layers have the same opacity and blending mode options as image layers, and you can move and reposition them just as you do image layers. By default, Adjustment Layers are named for their type (for example, Brightness/Contrast, Posterize or Invert).

You can always go back and modify the Adjustment Layer settings without affecting the original image data using the “built-in” Layer Mask.

A cautionary note here. Adjustment Layers can be “too much of a good thing” if you use too many of them. Excessive Adjustment Layers can lead to a cluttered Layers Panel, potential performance issues with large files, and complicate managing and tracking edits within an image or project.

And I’m sure we’ve all heard stories where people have gotten called out for over manipulating photos. You certainly don’t want that to happen!

Working With Adjustment Layers

Full disclosure: This post gets rather lengthy due to the number of Adjustment Layers to cover and all of the illustrative images. You certainly don’t have to read through the whole post at one sitting. Just be patient; I tried to keep most sections as short as possible. If you don’t have the time or just aren’t inclined to read the entire post, please bookmark it so you can come back to it at a later time.

There are currently eight Adjustment Layers in Photoshop Elements:

I used the Levels & Hue/Saturation Adjustment Layers last week working on those glowing antlers. But I may not have clearly explained what I used those adjustments for. It may have been obvious but just in case it wasn’t, today I’ll give a quick explanation.

A Levels Adjustment corrects tonal values (shadows, mid tones & highlights) in the image while Hue/Saturation adjusts colors in the image. If you read last week’s post you have already seen how those two adjustments work.

I will go into more detail today about each of the other 6 Adjustment Layers.

Brightness/Contrast

This Adjustment Layer is used to lighten or darken the image.

I’m going to spend some extra time going through this first Adjustment Layer giving you specific details about portions of the options dialog box that are consistent across all Adjustment Layers. So, this first discussion hopefully will be the longest of the six 😉

I’m going to be using the photo above of a hand with a green leaf from Pexels to show you some examples using the Brightness/Contrast Adjustment Layer.

When I select that Adjustment Layer using either of the methods I mentioned earlier, PSE ultimately opens the Brightness/Contrast dialog box and places a layer named Brightness/Contrast 1 directly above the active “leaf” layer:

Notice that the Brightness/Contrast 1 layer automatically comes with a Layer Mask. If you read last week’s post you know I used the layer masks on the Adjustment Layers when I was creating those glowing antlers.

I probably should have made sure you knew more about how to use Layer Masks. Just in case you aren’t sure, I did provide guidance on using Layer Masks in my “Thread The Needle” post from April 9, 2024. But here are some quick points for easy reference.

There are four major things that are important to keep in mind any time you are working with a Layer Mask:

1. The Foreground & Background Color Chips are an integral part of the process and should be set to the defaults. Just press D & PSE will set them to the default of Black & White respectively.
2. Make sure that the Layer Mask (in the Layers panel) is the active layer before masking. Just double-click on the Layer Mask to ensure it is active.
3. When working on a Layer Mask, black conceals (erases) & white reveals (restores).
4. Pressing X will swap between the Foreground & Background Color Chips any time but is particularly handy when you are working on a Layer Mask.

When the Layer Mask (far-right thumbnail) attached to an Adjustment Layer is completely white, the adjustment effect is applied to all portions of the underlying layer(s). If you don’t want to apply the effect to certain portions of the underlying layer(s), paint the corresponding area of the mask with black.

Ok, so that’s Layer Masks in a nutshell.

I’m really trying to keep this post from getting too long so I’m only going to provide a couple examples demonstrating results for this and the remaining Adjustment Layers.

Let’s revisit the Brightness/Contrast dialog box above:

There are only two settings I can change: Brightness and Contrast. As far as I am aware, anytime you create a new Adjustment Layer, PSE opens the associated dialog box with the default settings for the image. For Brightness/Contrast both are set to 0 (zero).

The maximum value that can be set for Brightness is 150 and for Contrast it is 100. The minimum value that can be set for each is minus 150 and minus 50 respectively.

If I move the dialog box closer to my image file, I will easily be able to see how the image changes as I make adjustments to those settings:

If you look at the lower left corner of that dialog box you will see two small icons which I’ll explain quickly.

Dialog Box Icon #1

The first (leftmost) icon looks like a box with a downward facing arrow to the left with a line drawn diagonally through that arrow (I call this the clipping icon). This indicates that the Adjustment Layer will apply to all layers beneath this Adjustment Layer.

I only have one (non-blank) layer in my file so that doesn’t matter in this instance. But if I had more layers beneath this photo that I don’t want to change, then I could click this icon and PSE will clip this Adjustment Layer to the layer directly below (the active layer). If I do click this icon, that diagonal line through the arrow will disappear.

Note: If your “clipping” icon doesn’t have a line through its arrow when you see this dialog box for the first time, that means you checked the “Use Previous Layer” box when creating the Adjustment Layer using the “Tool Bar” option and it is already clipped to the layer below.

Another little pointer. You don’t have to make any decisions at this point about clipping the Adjustment Layer to the previous layer regardless of how you create it. You can manually clip it later the same as you would clip a paper or photo to a shape, text or other element layer. This little icon just makes it easier😉

Dialog Box Icon #2

The next icon looks like an eye. This toggles the visibility of this Adjustment Layer. If you click this eye icon you will notice that the eye to the left of the layer’s thumbnail in the Layers Panel will also turn off/on:

You could just as easily go over to the Layers Panel and turn the layer off. This little “eye” just makes it a tad bit easier. Either way, turning the Adjustment Layer of/on will let you toggle between the “before and after” versions of your image while making the adjustments.

Making Adjustments

Now on to the adjusting part. Back to the leaf photo:

I’m going to move the Brightness slider all the way to the right (setting at 150) and the Contrast setting all the way to the left (Setting at minus 50). And here is a before & after version of the photo:

The left side is the original and the right side is after the adjustment was applied. Now I’m going to change the adjustment so that the Brightness slider is all the way to the left (setting at minus 150) and the Contrast setting is in the middle (Setting at 0). And here is a before & after version of the photo:

Again, left is the original and right is after the adjustment. Now Let’s do something a bit different.

I only want to change the background, not the hand holding the leaf. So, I’m going to make a selection around the hand/leaf:

Note: You can use whichever selection method you prefer. If you need tips on making a good selection, please refer back to my March 5, 2024 post about making the Right Selection.

I can now do one of two things.

#1: I can create a new layer via copy (Ctrl+J) using that selection. And then move that new copy of only the hand holding the leaf above the Adjustment Layer and change the adjustment so that the Brightness is set at minus 86 and the Contrast is set to 60.

Or #2: I can invert the selection (Shift+Ctrl+I) and apply the adjustment only to that portion (the background). However, I can only do this when creating the Adjustment Layer so I’m going to pretend I don’t already have a Brightness/Contrast Adjustment Layer created.

With the selection inverted I create a Brightness/Contrast Adjustment Layer and set the Brightness to minus 86 and the Contrast to 60.

Either way I end up with the exact same result:

Again, left is the original and right is after the adjustment. So how you go about adjusting only a portion of your image is completely up to you. If one way feels easier to you than another, then use that method.

To go a step further, I’ll make the difference a bit more dramatic for you. I’m going to apply that same adjustment to everything EXCEPT the leaf after making a selection of only the leaf and inverting the selection. And here is the result:

Not to over complicate things, there actually is one more way that I could have done either of these “partial” adjustments. I’m going to go back to the original photo (no Adjustment Layers) and create a fresh Brightness/Contrast Adjustment Layer and set the Brightness to minus 86 and the Contrast to 60.

Now, with the layer mask on the Adjustment Layer active and my color chips set at the default (Foreground black & Background white), using a hard round brush, I just brush over the portion(s) of the photo (in this case the leaf) revealing the original color. The end result is the exact same thing you see in the image directly above. But this time the layer mask looks like this:

I hope by now you can see just how powerful and versatile Adjustment Layers can be.

Let’s take a look at the rest of the Adjustment Layers. Hopefully, those will go at least a little quicker 😉

Gradient Map

Another full disclosure moment here…this one did get longer than I’d hoped. But still not quite as bad as the Contrast/Brightness discussion.

This Adjustment Layer is used to apply a gradient map to an image layer. Before I go further, I want to explain the difference between using the Gradient Tool and using a Gradient Map.

Note: This Adjustment Layer works identically as when going to the top tool bar and clicking Filter->Adjustment->Gradient Map. Just remember Filters are destructive modifications.

The Gradient Map is a tool that allows you to use gradients in a non-linear way to change the colors of an image while preserving the original image’s shading.

Conversely, when using the Gradient Tool (or a Gradient Fill) PSE adds a gradual transition of color to a layer. You can choose from gradient presets or create your own.

Clear as mud, right?!? It took me what seems like a long time to figure out exactly what this Gradient Map “tool” is really all about. What it boils down to is, this is NOT at all like using the Gradient Tool or a Gradient Fill Layer.

In short, a Gradient Map replaces a predefined shade of grey in an image with a color or value of your choice. Gradient maps can create interesting effects when applied to photos or other images.

A more technical explanation is that PSE calculates the brightest and darkest parts of the image. The color used for the adjustment is applied in a gradual manner from the darkest value to the lightest. With the dark value(s) being applied to the darker color(s) in the image and the lightest value(s) being applied to the lighter color(s).

Now let’s look at the Gradient Map Dialog box:

The initial map color will be set to the value of my Foreground color chip (black) which I can change and I’ll show you how in a minute.

I first want to talk about the two options; Dither and Reverse. Dither adds random noise to smooth the gradient and reduce banding effects. Reverse switches the image to a negative. Sounds simple enough.

Now, to change the color all I have to do is click anywhere within the gradient color “strip” at the top of the dialog box. PSE opens the Gradient Editor box:

When this editor opens, the default “map” (the Name field) is set to Foreground to Background. From here I can select one of the other presets and adjust the color(s) as I choose.

You should be able to see the line of color below the window of presets. You should also be able to see that at each end of that strip there are boxes at the top and bottom of the strip I call these “color stops”. The top box (at either end) allows me to change the Opacity for that color stop. The bottom box allows me to change the color used.

If I select the Foreground to Transparent preset (second from the left) and leave my Foreground color chip at black, PSE changes the entire image to a solid black. So, there’s not much point in showing you that.

Now, if I change the left color stop in the Gradient Editor to a goldish color (#ce9815) I get this:

Again, not quite what I expected. This looks more like a negative now even though I did NOT select Reverse in the Gradient Map dialog box. If you’re not confused…please tell me what you know that I don’t 😉 Just kidding. This particular adjustment layer is a puzzler for sure.

Now, if I delete that adjustment layer and start over with my Foreground color chip set to that same goldish color and keep the default “map” of Foreground to Background, I get this:

Well, that still doesn’t look at all like a “normal” gradient…does it? That’s because PSE is applying the colors in a linear manner based on the color values within the image.

I can set (or even add) color stops to have different colors which will give different results such as this:

Again…this looks more like a negative. I’m going to go back to the version that I got with my Foreground color chip set to that goldish color and the default “map” of Foreground to Background:

I can play with changing the Blend Mode and Opacity on the Adjustment layer to get additional results. I set the Blend Mode to Color Dodge and the Opacity to 80% and got this:

That’s actually not too bad! Now I’m going to try one more thing. I’m going to use the layer mask and brush away some of the gold on the leaf:

So, it’s not a complete bust after all. Just goes to show what you can accomplish with Blend Modes, Opacity changes & Layer Masks.

I could show you other examples using some of the other presets. But I think you can likely guess where that’ll take us 😉 And there are lots more than what you see in this first “Default” set:

If you’re at all interested in playing around with this adjustment, I’d encourage you to do so. At least now you may have a better idea about what you can expect. I can tell you this; I very rarely ever use this Adjustment Layer.

One final note. It is possible to apply this adjustment to only part of an image, just as I did with the Brightness/Contrast Adjustment Layer.

Photo Filter

This Adjustment Layer is used to adjust the color balance and color temperature of the image.

Note: This Adjustment Layer works identically as when going to the top tool bar and clicking Filter->Adjustment->Photo Filter. Just remember Filters are destructive modifications.

This time I’m going to use a different photo. I thought this nice ocean sunset from Pixabay would give us a better feel for how this adjustment works:

With this photo open in PSE, I create a new Photo Filter Adjustment Layer and PSE opens the Photo Filter dialog box:

The values you see above are the default settings for the Photo Filter (at least in my version of PSE): Filter = Warming Filter (85), Color = orange (#ec8a00), Density = 25% and Preserve Luminosity is un-checked. The default Color in this dialog box will change based on which Filter I select.

There are nineteen other options available for the Filter selection. Just click the down arrow at the end of the Filter field to view all the choices:

By default, all of the Warming Filters will use some variation of an orange or yellow: (85) uses #ec8a00, (LBA) uses #fa9600 and (81) uses #ebb113.

All of the Cooling Filters will use some variation of a blue: (80) uses # 006dff, (LBB) uses #005dff and (82) uses #00b5ff.

The Underwater Filter (last on the list) uses an aqua color #00c2b1.

The remaining “color named” Filters will default to some shade of whatever color is shown in the name; Red, Orange, Yellow, etc. These Filter options are in essence, presets.

Note: Regardless of the filter I select (in this case the Underwater filter), if I attempt to change the default color, PSE automatically unchecks the Filter option, checks the Color option and changes the color chip to whatever color I selected:

As soon as the Photo Filter dialog box opens, the default Filter type is applied to my photo. I’m going to go back to the default Warming Filter (85) so I can show you the difference between the original photo and the “warmer” version without having changed the Density setting (25%) or checking the Preserve Luminosity box:

That’s a relatively subtle change. But if you look closely, you should be able to see how the “waves” around the rocks look less blue in the bottom photo. They now have a warmer tone…almost a hint of pink. And the same happens with the colors in the sky which also now look darker. It’s exactly that warmth that these “warm filters” are meant to provide.

Now, do you remember that I did not check the Preserve Luminosity box? I did that for a reason. I wanted to explain how this “luminosity” option works.

The “Preserve Luminosity” option keeps the brightness levels of the image consistent even while altering the color with a filter. Only the color cast will change; essentially, it prevents the image from getting significantly darker or lighter when applying the color filter.

In simpler terms, if this option is NOT checked, the brightness of the image will be affected. Conversely, if this option IS checked, a subtle color tint is added to the photo without significantly affecting the brightness levels.

When I check the box for Preserve Luminosity this is how the photo changes:

I hope you can see the difference. The top photo has a much darker cast to it than the bottom photo. I almost always Preserve the Luminosity of any image I modify with the Photo Filter. That doesn’t mean you have to. I just think it’s best not to monkey with the luminosity. I have found with certain types of photos the difference can be striking and not in a good way. But you are certainly welcome to play with this setting to see how it works on your photos.

When I select either of the other warming filters the change is negligible. So, I’m not going to bother showing those. What I will do is show you how changing the Density setting affects the photo.

With the Photo Filter options now set at Warming Filter (85) & Preserve Luminosity checked I’m going to change the Density. As you can see, the Density field has a slider so I can either make the adjustment using the slider or by simply typing in a value where it currently is set to 25%. I’m going to go with 75% just to show you a less than subtle change:

Can you see how the entire photo now has a more pronounced color cast? I don’t know about you but I wouldn’t want the water to look so orange. That setting, to me, makes things look rather unnatural. But changing the density in subtle ways can come in handy. Just don’t get too extreme with that adjustment.

Next, I’m going to show you the Cooling Filter (80). Again, I’m going to check Preserve Luminosity and keep the Density at 25% (the default):

It should be easy for you to see how much bluer things are in the bottom photo. Based on all the other things I showed you with the Warmer filters I think you already have a good idea about how this Photo Filter works.

I would encourage you to play around with all the other Photo Filter options, including the various colors. As I mentioned when I showed you the Density changes…just be careful not to get too extreme. Unless of course you’re purposely looking to create an “other worldly” look for your photo 😉

One final note; it is possible to apply this adjustment to only part of an image, just as I did with the Brightness/Contrast Adjustment Layer.

Invert

This Adjustment Layer is used to produce a photo negative effect by creating a negative based on the brightness values of the image.

Note: This Adjustment Layer works identically as when going to the top tool bar and clicking Filter->Adjustment->Invert. Just remember Filters are destructive modifications.

This one will be super short to explain. As I said above, Invert produces a photo negative effect. There are no options for this Adjustment Layer so PSE opens this dialog box:

I’m going to go back to the hand holding a leaf: Here is that photo after applying the Invert adjustment:

So, you might be thinking…”How is this any different than using the PSE Shortcut Key Ctrl+I?” The initial result is identical. But you can do more by using the Adjustment layer.

Just because there are no options that let me modify this adjustment doesn’t mean I can’t alter the image in other ways. If I set the Opacity of the Adjustment Layer to 60% I get this:

That’s a different look…almost on the eerie side. Now if I set the Opacity back to 100% and change the Blend Mode to Luminosity, I get this:

That’s an interesting look. If I now lower the Opacity to 30% at this blending I get this:

I actually like that. It looks close to the original photo but with some “fog”. Now, if I leave the Opacity at 30% and change the Blending Mode to either Hue or Color, I get this:

Again, another nice result. To me this looks almost as though the photo was taken at dusk.

Clearly you can see that you can do more with this Adjustment Layer than just create a “negative”. Playing with the Opacity and/or Blend Mode can definitely make this a more useful Adjustment Layer!

Once again, it is possible to apply this adjustment to only part of an image, just as I did with the Brightness/Contrast Adjustment Layer.

Threshold

This Adjustment Layer is used to render the image in monochrome with no gray, so that you can locate the lightest and darkest areas.

Note: This Adjustment Layer works identically as when going to the top tool bar and clicking Filter->Adjustment->Threshold. Just remember Filters are destructive modifications.

The only option in the Threshold dialog box is a slider that allows me to “scroll” either darker (right) or lighter (left). And I could also simply type in a value where it currently reads 128 (default). This adjustment produces only black and white versions of the photo as I change the Threshold setting.

I may be missing something here. I can’t think of a time when I ever needed to just “locate” the lightest or darkest points in an image. I do know that when working with black and white photos, accurately setting the blackest point and whitest point is crucial for achieving the desired tonal quality.

I suppose if I were a professional photographer, it may somehow be important to me. But there are other tools in PSE that I use when dealing with black and white images. One of which is the Levels Adjustment Layer.

I really don’t know what else to tell you about this Adjustment Layer.

Posterize

This Adjustment Layer is used to give a flat, poster-like appearance to a photo by reducing the number of brightness values (levels) in the image, thus reducing the number of colors.

Note: This Adjustment Layer works identically as when going to the top tool bar and clicking Filter->Adjustment->Posterize. Just remember Filters are destructive modifications.

Again, the only option in the Posterize dialog box is a slider that allows me to “scroll” the Level setting. And I could also simply type in a value where it currently reads 4 (default). If I set the Level to the maximum (255), the original photo remains unaltered. If I set the Level to the minimum (2) I get this:

In my experience using a Level setting much higher than 10 doesn’t result in a significant posterization. But I suppose that can also depend on the photo to which it’s being applied. I’m just letting you know what I’ve generally found with this adjustment.

One final thought on Posterize. There is another way to “posterize” an image that I feel gives me a wider range of options. I can go to the top tool bar and click Filter->Artistic->Poster Edges.

I talked about using this filter in my “Filters On Paper” post on May 14, 2024. If you want more information about how this filter works, I’d encourage you to read that post. Just remember that Filters are destructive modifications.

So that concludes today’s discussion about the different Adjustment Layers in PSE. I hope you found it interesting and informative albeit a bit too long.

Merging Adjustment Layers

Why would I merge Adjustment Layers in PSE? Simply put, I would do this to apply the adjustments made in those layers permanently to the image, essentially “flattening” them into the underlying layer, which can be useful when I no longer need to modify the adjustments individually and want to streamline my workflow or reduce file size.

Before you get confused about Merging being like Flattening an image; they are very different. There is a specific option in PSE to Flatten images:

So how is that different than merging? In PSE, merging basically only combines layers into one. As I mentioned above, this essentially “flattens” the selected layers into one layer. But it does not truly flatten the image. Confused yet? I know I was when I first looked into the difference years ago.

Flattening merges all selected layers into a single “Background” layer. The key word here is Background.

Let’s say I have 4 different Adjustment Layers applied to my “leaf” photo which has it looking like this:

This is how my Layers Panel looks:

Pay particular attention to the “empty” part of the canvas…not just the photo. If I select and merge these five layers and save this as a PNG image then pull that image into a new document with a colored background. It looks like this:

Notice the PNG retained the blank space around the photo allowing the new background to show underneath.

Conversely, if I had selected those same 5 layers and had gone to the top tool bar and clicked on Layer->Flatten image this is what happens:

Do you see the white background behind that photo? I clearly don’t want that. If I were to now save this image as either a PNG or a JPG file, that background will be there. That means if I pull the saved PNG file into that same new document with a colored background it will look like this:

Generally speaking, you likely don’t ever want to flatten an image unless it fills the entirety of the canvas. If an image fills the entire canvas, it by nature becomes a background in and of itself. Consequently, there’s no space for PSE to “create” any additional background. Even with that, I’d highly recommend that you stick with just merging layers.

It is important to remember that once merged, Adjustment Layers are no longer editable making them destructive edits. So, if I feel I may need to go back and change any adjustments later, I need to duplicate the layers before merging. Also important…I cannot use an Adjustment Layer as the base or target layer for a merge.

If you need more information about exactly how to merge layers, please refer back to my File Size post from July 11, 2023.

More Adjusting Tips

An Adjustment Layer will affect every layer beneath it. So, if you have more than one layer in your file and you want the Adjustment Layer to affect only one layer in your file, you will need to clip that Adjustment Layer to the specific layer you want to modify.

If you want to make an adjustment to only part of an image all you have to do is make a selection of the area to which you want to apply the adjustment.

Do not be caught off guard by the Gradient Map Adjustment Layer. It does not behave at all like the Gradient Tool or a Gradient Fill Layer.

If you are looking to merge your layers simply for size management purposes, Adjustment Layers with masks (the layer’s rightmost thumbnail in the Layers panel) that contain only white values do not add significantly to the file size, so you don’t need to merge these Adjustment Layers simply to conserve file space.

When using more than one Adjustment Layer consider the order of those layers as the effects will be applied cumulatively. Rearranging the order can change the end result.

Applying too many adjustments on a single image can lead to an unnatural look, where the image appears overly manipulated.

A large number of Adjustment Layers can slow down your software, especially when working with high-resolution images.

Remember you can use Layer Masks and Blend Modes on your Adjustments Layer for more complex adjustments.

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