How To Increase The Resolution of a Photograph in Photoshop

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Problem: You've got a small digital image, and you wish it were bigger; you could make it bigger, but then it would just look blurry. Conventional wisdom would have it that you are out of luck. However, I disagree All you have to do is trick the eye into thinking that there is more resolution!

For this example/tutorial, I will start with this picture of the band Diary of Dreams (500x33). It looks like it would make a cool desktop background...if it were bigger (in my case, 1440 x 900).

[original image]


1) Enlarge the image. Obviously, a good first step. You'll want to use bilinear interpolation but that will be done by default anyway. As you can see the main problems with the image at this point are the magnified jpeg artifacts, a very "mottled" look, blurry edges, and lack of detail.

[enlarged image]


2) The first thing we can do is apply a "Surface Blur" to take care of a lot of the mottled spots and jpeg artifacts while preserving edges. For this image, radius=5 threshold=11 is pretty good.

[surfaced blurred]


3) It's still too mottled in certain areas. For example, in the lighting behind the performers head: this tells your brain that it is an enlarged image! Also on all the big regions like arm, etc. So pick a large feathered brush (~ 100) go into mask mode and manually paint a selection that covers all the areas that you'd like to smooth out more. Then Gaussian blur those areas.

[selection mask]


[Gaussian blurred]


4) Now for the key step: adding detail. You need to add lines and details that are at the resolution of the new image, smaller than the smallest lines in the small image would be after being blown up. When you look at a picture, your brain is automatically going to make an assumption about what resolution it is and your imagination will fill in the rest. Your job here is to convince the viewer that the resolution is high and do this by creating enough small little lines and stuff. It's not hard! But it does take a little artistry. Just get a relatively fine brush and paint some highlight / shadow edges in places.

[details]


For example, I added detail to the folds of cloth, little strands of hair, and sharp highlight edges, etc. Then I manually made a lot of the edges that looked blurry a bit sharper by painting over them.

5) Now let's add just a tiny bit of a "film grain" to lock this in as the new resolution. Since the image is so smooth, the film grain helps a bit to make it look more real. But don't overdo it. I applied it on a new layer (monochromatic Gaussian noise, amt = 0.59) and then blended it 50% with the previous layer.

[final+grain]