Resizing Multiple Photoshop Layers

[Lon Howard]

Another question about fundamentals I never learned. Although I've used photoshop layers for about ten years in my own made up way, I do realize that it probably isn't how good photographers work - i.e., I never got into much minutiae, I just tried different things until I made something happen. So now I'd like to understand layers more completely. Here's the latest thing I puzzle over. I went through this Adobe tutorial on resizing multiple layers.

https://helpx.adobe.com/photoshop/ho...ize-layer.html

I downloaded all their practice images and waded through and eventually made everything work. But after I got to the end, having successfully resized all those layers, I thought, "Now what? Where do I go from here? What do I do with all these layers?" I thought maybe there'd be a before or after result, or that the next tutorial in the series would provide some light on the reason for doing all this, but there was nothing.

It was then I started searching online for the "why do this?", but everything is all about how to do it, not why do it in the first place.

So, is this kind of procedure mostly about producing a composite? What kind of situation benefits from resizing that many separate layers? What end result benefit does it provide?

Thaaanks!

[Manfred M]

Photocompositing is definitely one reason to do this, but not necessarily just to do complex composites. I will use this technique when doing sky replacements. Sometimes there is an issue with part of an image and I might "steal" a part of another image to improve the one I am working on. It could be as simple as grabbing a catch-light in an eye or even replacing an eye or some hair, etc.

It can also be used if you want to put your signature or logo on an image.

I use it a lot when I am printing. I generally do test prints of images and might put a couple of variations of a print on a single piece of paper or do the digital equivalent of a contact print. I always use it when I do a final print. I prepare a print and copy it onto a properly sized image the size of the paper I am using to ensure the print is positioned where I want it on the paper (the printer will centre it, and that may not be what I want.

[pschlute]

In the example you have three photos each in a different layer. You use the transform tool to resize and place each image where you want then you can create a JPEG or TIFF from the PSD file. You can collapse the layers before "saving as" if you want to make a TIFF file.

Where you may find this technique more relevant is if you want to add an object (say a car) from one photo into another. Open both images in PS. Working on the image that contains your car select it with one of the object selection tools then right click and select "layer via copy". Then click and hold that layer and drag it into the other photo. Then use the free transform to resize and move the car to where you want it.

ps it will help if the pixel dimensions of the two photos are the same or the one with the object is larger, as you can always reduce the size of the selected image (car) in the transform process. Increasing the size of the object may give you a problem in terms of resolution.

[Stagecoach]

Here's a typical composite using the procedure comprising of 7 different layers of individual people plus a background.

Each of the 7 layers could be individually adjusted in size to fit 'best' along with positioning. Not a finished work, just a play piece.

[Lon Howard]

Very good information, all! I'm working on something to get started with ...

[Lon Howard]

My first composite and first go at resizing layers. Transported the lady from Grand Bahama Island to Kintla Lake in Glacier Nat'l Park. The major hurdle was trying to get some realistic perspective. She's very tall and once I got her onto the ramp, the railing handles came up almost to her shoulders - way too high. I downsized the ramp layer a couple times to get it lowered enough to look somewhat normal, but ended up having to crop off more of the sky than I wanted. Am wondering if there's anything else I could've done.

[pschlute]

Why did downsizing the ramp image lead to you cropping the image ?

You should have resampled it to a lower resolution but left the "crop" the same

[Manfred M]

Where to begin...

You are right, the proportions look wrong. A good ruie of thumb is to use images where the focal lengths are about the same. The proportions just look wrong. Ideally both the subject and the background will have been taken with roughly the same focal length and aperture. The closer you are to matching the two, the more realistic the composition.

Other things to watch for include the colour temperature and direction / intensity of light. The light in your background is diffuse and cool, but your subject has distinct shadows and the colours are warmer.

Your subject also looks like she has been cut out and is floating on the ramp; normally we expect some shadows where the shoes meet the ground.

Finally,there are all kings of artifacts visible on the subject; pieces that suggest you've cut her out. The arms, legs and hair give that away.

Doing this well is one of the most challenging things one can do in photography. Good start, but keep on refining and learning.


This is a recent photocomposite I did:

Photocompositing - Our Dystopian World II

[Stagecoach]

Manfred has mentioned the obvious selection errors visible of the subject and I'm wondering why they are there.

Having recently delved into selecting 'people' with PS I have found that the 'Object selection tool' does an excellent job on almost everything except the hair. What tools are you using for the selection?

[Lon Howard]

Thank you all for your insight. Apparently there are a number of dissimilar components working against this effort. Focal length and aperture was 55/f8 for the subject and 40/f22 for the ramp. Warm sea level Bahama and cool 4,000 ft lake. Looks like I should update to ps 2020 to get the Object Selection tool - I used the Quick Selection tool - lots of adding and subtracting .

Actually I don't know if downsizing the ramp layer caused the need to crop - I just know that there wasn't enough of the image left at the top so I had to crop just a little. The original ramp capture didn't leave much sky to begin with, so just a small crop seemed to matter.

Lots of good suggestions, thanks again.

[Manfred M]

Lon - Grahame is right about the Subject Selection being very powerful, but it is not perfect and I will sometimes use it in conjunction with the quick selection tool and other selection methods. For many subjects, I will often resort to the pen tool. It is a great tool to use but a fiendishly challenging learning curve. For hair I will use the select and mask tool, but again, hair can be fiendishly challenging to do.

I use layer masks in all of my composites, rather than cutting something out and pasting it onto a base layer.

When it comes to matching the image tones, I will generally use a clipping mask and will use one of the adjustment tools to match the tonal family of the subject and the background.

Watching the direction and quality of light is also important; if those don't blend properly, that is a dead give-away that you have composited the images. Dodging and burning certainly can smooth over the differences, so an extent. When I have a background, I like shooting the subject in the studio because it lets me do a much better job lining up the lighting. The image I link to in #8 is a studio shot of the model and I used overhead and back lighting to fit the background I was grafting to.

Finally, make sure that you connect your subject to the image through shadows. Even on a heavily overcast day, there will be a shadow where your subject interacts with the underlying image. Direction and intensity are important.

The problem that you have to overcome when compositing is that we have been looking at scenes all our lives and if something looks off, we will notice it even if we don't recognize exactly what is wrong.