In my critic group I was explaining the steps I take to cleanup photos of my paintings. There was a fair amount of interest, so I thought I’d write it up for those that are curious. Following this process I can now reliably touch up a photo in just a few minutes.
First - it's a good idea to have your computer monitor calibrated. I use a product called 'color munki' from x-rite. Otherwise you might adjust a photo to look good on your monitor, but it will look wrong/incorrect elsewhere. The first time you calibrate your monitor you will probably find that the monitor needed to be tweaked quite a bit (which incidentally also points out that anyone viewing your work without a calibrated monitor is likely to see variability in the colors, so don’t get too worried about perfection if you are only cleaning up photos for use on the web).
I photograph artwork in my studio. I'm fortunate that I have good natural light, and I often rely on this. But I also have good artificial light with a mix of full-spectrum bulbs - and I find I can take photos at night with acceptable results. The photo must be in focus and evenly lit with no hot spots. But color temperature and dim lighting can be adjusted. The photo should also be nice and square in the viewfinder (it should look like a rectangle with 90 degree corners – not like a trapezoid).
Once I have the photo, these are the steps I take with Photoshop to clean it up:
- Crop - cut the photo down to just the artwork. Be sure to square up the horizon line at this point if it doesn't appear level. In photoshop you can correct the horizon by dragging the mouse outside the crop box to slightly rotate the image to get the horizon level if necessary. Another great trick is to shrink the crop box so that the bottom edge overlaps the horizon, then rotate so the bottom of the crop box aligns with the horizon, and then re-stretch the crop box. This takes a lot of the guesswork out of the alignment process.
- Levels - Under Image->Adjustments->Levels you will find a tool that shows a spectrograph of how much information you have across the full value range. You’ll almost always find that you have no information within the darkest darks or lightest lights. With this tool, you can slide the sliders to ‘cut out’ these unused area, and photoshop will re-stretch your existing values across the full value range. This makes a huge difference.
- Color Balance (Image->Adjustments->Color Balance) - this lets you separately adjust the highlights, midtones and shadows. I find that if I adjust the highlights very slightly towards yellow and the shadows very slightly towards blue this usually brings the photo closer to the original artwork.
- Exposure (Image->Adjustments->Exposure) - sometimes I take the exposure down just a touch if after these previous steps the photo seems too bright or over saturated.
If you’re unfamiliar with the tools I’ve mentioned, use Photoshop help to get some additional instructions on using any of these tools. Good luck.