Join Julieanne Kost for an in-depth discussion in this video Merging and flattening layers, part of Photoshop CC 2018 Essential Training: The Basics.
- [Instructor] As your documents begin to contain more and more layers, sometimes those file sizes will grow to be quite large, so people are always looking for a way to reduce the file size, but unfortunately, the different ways that PhotoShop has to merge layers or to flatten images also removes some of their flexibility, but let's take a look at them so that you can decide for yourself. Right now, at the document size in the lower left hand corner, you can see that if this document was flattened, it would be about 12 megs, but as a layered document, it's 52.4 megs, so let's see if we can get that file size down.
Now one of the ways we could do this is by cutting or cropping any extra information that's actually outside of the visible canvas area, so when we first brought this orange file into this document, it was actually a little bit bigger, so there's actually some orange that is kind of hanging out here, outside of the canvas area, so if I wanted to crop that, I could do a quick Select All, and then, in Image, and then Crop, and we can see that now, instead of being 52 megs, it's down to 45, so that did crop off some extra information.
It did decrease the file size, but of course, if I wanted to access that extra information, well, it's now gone, so I can't. All right, let's go ahead and Deselect that, and let's take a look at another technique used for merging layers together. I'm going to select all four of these small photos here in the small photos layer group, and I'll choose the Layer menu, and then, choose Merge Layers. So we can see that the file has been decreased in size to about 26 megs, so that did help, but it also took away some flexibility.
For example, what if I want to swap the peppers and the tomatoes. I want to reposition them. Well, I certainly can still do it because nothing was lost as far as the fact that the images weren't overlapping, so it wasn't a permanent change, but I would have to copy it to its own layer, and then I'd have to reposition it, so it's just a little bit more inflexible this way. Now, if I flatten the document, that makes it very inflexible.
I'll go back to the Layer menu, and then, I'll choose Flatten Image. You can see now in the Layers panel, I only have a single background layer, so if I wanted to reposition the logo, for example, well, I really can't. It's been flattened or merged with all of the layers underneath it. Now, a lot of people think that they need to flatten their images before they save out a jpeg file, but that's not true, so let's undo some things here. We'll go back in time. I'll undo the flattened image, and I'll also step backwards one more time, so that we have all four of our individual layers there because I don't want to accidentally save over the original.
What I'm going to do is choose File, and then, Save As. Under the file format area, I'm going to change this from Photoshop to jpeg, and because the jpeg file format doesn't support multiple layers, that's no longer an option here. I'm going to append this by adding an underscore f so that I know that this is my flattened file. I'll also know that it's different from the original because it has the dot jpg after it as opposed to the dot psd, and then, I'll click Save.
I get to select my image quality, and in this case, I'm going to move it all the way up to 12, and then, click OK. This will give me a larger file because I'm telling it it can't compress as much, but it's going to give me a higher quality image as well. When I click OK, you'll notice that on my Layers panel, I still have all of my individual layers, and that's because when I did that Save As jpeg, PhotoShop saved out a copy of the jpeg, and left the original psd open for me to continue working.
So if we scoot over to Bridge, we can actually see there is the exported jpeg file. Now in future videos, we'll talk more about different export options, but for now, to maintain the most flexible workflow, I would recommend that you don't merge or flatten your layers just in case you want to make changes to your documents in the future.
Julieanne reviews the basics of digital imaging—from working with multiple images to customizing the Photoshop interface to suit your needs. She shows how to use different Photoshop tools to crop and retouch photos, while always maintaining the highest-quality output. She also demonstrates the most efficient ways to perform common tasks, including working with layers, making selections, and masking. Along the way, she shares the secrets of nondestructive editing using Smart Objects, and helps you master features such as adjustment layers, blend modes, filters, and much more—increasing your productivity every step of the way.
- Opening documents in Photoshop
- Opening files from Bridge and Lightroom
- Working with multiple documents
- Panning and zooming documents
- Customizing the Photoshop interface
- Modifying keyboard shortcuts for speed
- Understanding file formats
- Choosing color modes, bit depth, and color space
- Cropping and transforming images
- Working with layers and layer masks
- Making selections
- Removing distracting elements
- Getting to know the blend modes
- Working with adjustment layers
- Applying non-destructive filters
- Getting to know the blend modes
- Applying filters