This is a tutorial about how to enhance an image by laying it on top of a background and blending the two layers to produce a pleasing image.
Click on the thumbnail image below and aquaint yourself with the labels. It will make it easier to understand this tutorial.
This is how to blend two images:
Open two images. I’m going to call the image you want to enhance, the ‘Starter Image’ (SI), and the background image the ‘Background Image’ (BI).
The BI should be something just this side of boring. I mean it should be an image that has interesting tones and colours and textures; but that’s about all. A close-up of a brick showing just the various colours and textures would be a good choice. For the BI in my example, I used a scan of a sheet of art paper that had been soaked in instant coffee and left to dry.
Make sure the two images are the same size or that the SI is smaller than the BI. If the SI is bigger than the BI, part of it will be cut off when it is laid over the BI. (see the end of this tutorial if you are not sure how to tell what the sizes of the images are, and there is a very short tutorial on what you need to know.)
Click on the SI. Select the whole image (Select > All). Then copy it (Edit > Copy).
You now need to move to the BI, so click on it to make it the active image (the one you can work on). Paste the SI over it (Edit > Paste).
You will now have two layers but the image you can see will just be the SI. it is as though the BI is not there. But it is; it is just obscured by the top layer. This will change if you change the way the two layers are blended together. The way to change the way the two layers appear relative to each other, is through the Blending Modes.
The Blending Modes are in a drop-down menu in the Layers palette. If the Layers palette is not visible, go to Window > Layers and the Layers palette will appear.
Examine it closely and you will see a drop-down menu, and below that you will see two small images of the SI and the BI, with the SI above the BI. That’s fine. it tells you there are two layers, even though you can only see one in images you are working on.
The default blending mode is ‘normal’. In this mode, the top layer completely obscures the layer below, which is why you can only see the SI. We can change that by changing the blending mode in the drop-down menu. Try ‘multiply’ and see what you think of the result.
See how the SI and the BI have interacted to produce something quite new and interesting.
Also try ‘overlay’. In fact, try all the blending modes to see what effect each of them has. ‘Multiply’ is a good one though.
The effect may be too strong, and if it is, just cut back on the percentage of the opacity slider at the top right of the Layers palette.
There are things you can do to blend different parts of the image by different amounts and ways to blend different parts of the image with different blending modes. The extra rectangle in my example – the one to the side of the top layer in the layers palette – is a vector mask which allows you to strip away part of the top layer with the brush tool. More about that in the next tutorial.
Click on Image > Image Size and a box will appear that has width and height in pixels, the document size in a variety of units of dimension, and tick boxes for Scale Styles, Constrain Proportions and Resample Image.
To check whether the SI is no bigger than the BI, you need to look at both the number of pixels in the Pixel Dimensions and at the Resolution in both images. Make a note of what they are for both images.
If the Resolution of the SI is very different from the resolution of the BI, you can alter the Resolution of the SI (or the BI if you prefer to change that) BUT whichever image you change, uncheck the Resample Image box. Click OK and then if you still need to change the Pixel Dimensions of the SI or the BI, check the Resample Image box and the Constrain Proportions box and alter the Pixel Dimensions.
That’s it except for one thing. Don’t Save the image with the changed image dimensions unless you really know you want to. If you have downsized your image and then saved it and quit the image, you will not be able to go back and recapture the pixels you threw away in downsizing the image.