What post-processing tricks can be used to improve the quality of photos taken with the on-camera flash?

Question

I know that the on-camera flash tends to produce poor images in general (the subjects are washed out, and the light from the flash isn't very powerful). But... sometimes there's no other choice but to use the on-camera flash and hope for the best. So I'm wondering, what is the best way to recover these images are in post-processing?

My question is similar to this question about fixing blown-out highlights; however, I'm interested more in things I can do to improve the entire image quality -- so this might include things like better color balance, ways to make the subject look less flat, etc.

I'm interested particularly in answers that use tricks or techniques that aren't necessarily "obvious", but might be considered "tricks of the trade" by professional photographers (I assume they have to deal with this problem sometimes, too?) -- I have both Lightroom and CS5, and am reasonably proficient with their basic use, but I know I'm probably just scratching the surface of their power. So nothing's off-limits for this answer -- if you have a solution, but it requires 20 layers and 15 different brushes, I'm all ears!

Edited to add: Note that I'm asking about photos that I've already taken, so any preprocessing tips are not helpful to me. Additionally, I do have a bounce flash, but there are certain settings in which it's not useful (if, say, there's nothing to bounce off of!), and the only way to get any light into the frame is direct hard light. My question is about how to make the best of these less-than-ideal shooting conditions in post-processing.

Answer 1

Here are a few ways I have fixed washed-out photos be it from the flash or just in general.

• Adjust levels - I will slide the black slider to the right to darken the photo. Sometimes if only part of the photo is washed out I will use a mask on the levels to darken only what I want to. This masking can get complicated and I recommend looking up some tutorials.

• Curves is another tool I have used but can be a bit tricky.

• High Pass Filter to bring details into the image and sometimes helps the washed out look. For a tutorial on the high pass filter check here.

• Shooting in RAW and adjusting the sliders sometimes is all that is needed

• Burn to image to darken where needed. You can do this in Photoshop non-destructively by creating a new layer, filling the layer with 50% Gray (Hex is #808080) then change that layers Blend Mode to Overlay, Then Burn on that layer (Dodge will also work on the same layer)

• Create a black layer and change the blend modes to soft light.

• Duplicate photo and change blend modes to see what helps darken the photo. Again advanced masking is sometimes involved and experimentation is required to see if this will work for your photo and what blend mode will work.

• Use a plugin like Topaz Adjust to change the photo.

• PS Photo Filters can help.

• I will sometimes use a combo of the above.

• The biggest trick is experimentation with filters, settings, etc in PS to see what happens. But always remember...HAVE FUN! =>

These are all done in Photoshop CS5/CS6. I do not have any examples I can currently post or I would.

I hope some of these help!

Answer 2

I know you are asking about post-processing tricks, but I'm going to offer a popup flash shooting trick that does wonders. Take a business card with white background and use it to bounce the flash to the ceiling and prevent the harsh light of the flash from hitting your subject directly. You can hold the card with your free hand, or if you make two small incisions you can mount it on the flash support.

Here is how it looks on my Canon Rebel XT:

Answer 3

Make a virtue out of it

I recently heard the saying "Go big or go home!" In that spirit (and if all else fails):

Make it look like you were going for that flat, washed-out look.
Aim for that hard-light, pap / glam look.

• Crank up the exposure (highlights) so most of the skin is burned out.
• Judiciously remove contrast.
• Either de-saturate or over-saturate, but do something; it's about making the image look intentionally unnatural.

Answer 4

Preprocessing with milk-bottles !!! :-) : As per Miguel's business card suggestion but use a piece of translucent plastic at an angle in front of the flash so that the light shines through and also reflects. A larger to much larger than business card piece that leans further forwards allows a larger area to be illuminated.
Cut at camera end to allow it to sit better.
Increasing the area that is radiating light gives softer and more shadow free lighting.

Here in NZ milk bottles are an about ideal source of plastic. Wash them well!
As a guide to desired opacity - placed against text it can be read with some reduction in quality. At 10mm it's almost unreadable, at 50mm it can be seen as a vague blur.

Post processing: Desparation only - adjust colour balance to add substantial and equal amounts of each of R + G + B. The image is now darker but still has ~= original colour balance. Increase Gamma until image is about "correct" brightness overall and now play in whatever way you normally would. It's hard to say why this makes he sort of difference that it does, but try it and see for yourself. "Overflashed images" can ofen be brought back to some semblance of usability.

Cheating: Convert to Black & White - an image which seems irretrievably damaged by flash nastiness can often be rendered acceptable or arty (maybe even both :-) ) by use of monochrome. Again - this is a personal preference thing and each must decide what is acceptable after doing this.