Forum: Photography


Subject: Help please

syntheticdreamer opened this issue on Feb 01, 2005 ยท 4 posts


DHolman posted Tue, 01 February 2005 at 4:12 PM

Hate re-working jpegs, but anyway ... this is a really quick fix and a little sloppy. I have to leave for work in a couple minutes. I only did the first 2 lights. This was an attempt to try and add more levels of tone back into that area. To do it for real would take a bit of care and more time. If you want to try it, let me know and I'll explain what I did. The problem is called posterization. There are usually 2 causes, first one is what GWFA explains above. The second is when you "step to hard" on an image when processing it. What that means is that by adjusting levels or curves or whatever else, you overstretch the data (usually seen as a comb-like look in your histogram). In either case, what it means is that you have too few levels of data trying to represent a lot of different tones. For instance, lets say you have lights like yours. There might be 100 different tones in that area going out from the very bright center to the darker edges. You may only have 5-10 tones available to represent that. So you end up with big areas of solid color that give you that ugly look instead of a nice smooth gradation. I can think of 3 solutions. First is, again, what gwfa suggests above. Second is, if it's not in the original image, you need to process it differently to limit the damage (meaning use multiple layers and blend). Third is, you can try to fix like I've done above, but it's a pain to get really good results and takes a little time. -=>Donald