Rule 1: If it Looks Good, then it’s Fine (part 1)

10 Basic Rules of Image Editing


Rule 1: If it looks good, then it’s fine (part 1)


Demystifying Image Editing

With Sagelight, one of my main goals is to demystify image editing. I mean, real, professional-level, artistically-expressive image editing.

To that end, I think that we tend to split image editing into two categories:

1. Doing the simple, automatic things like getting rid of red-eye, bringing up the brightness, cropping, etc, but nothing that’s going to make our picture “pop” or otherwise fantastic.

2. Anything else, which suddenly becomes difficult and forbidding — “not for me!”

I remember when I first saw a computer. This was in the 70’s, when computers were still mysterious, and my father’s company was having an “open house” day. They had computers running the first Adventure Game, the first Star Trek Game (for those who remember the text-version of those — they were awesome), etc.

Nothing incredible by today’s standards, but amazing technology back then.

I remember my father saying to me, “Press a button… go ahead“. Right after I nervously pressed a button, my father exclaimed, “Oh my God! you broke the computer!“. That made me instantly afraid of computers for quite some time. I only figured out years later (like 30 years) that he was just kidding. Well, you’d have to know the dynamic between my father and myself to know why It took so long to understand that… moving on…

Oh, those were the days.   Why do they have to grow up so fast?


The point is that computers became so mysterious because of the power they have by just pressing one button.  I think the same can be true of image editing.

We all get that there is some sort of science behind it, if nothing else because people like me who write image editing programs remind us of this fact all the time, by using terms like “Gaussian Blur” and “Unsharp Mask“, not to mention “Exposure” (I mean, what is that?), “Gamma“, “Curves“, RAW, “demosaicing“, “histogram“, “equalization“, and so-forth, and so-forth.

It suddenly seems mysterious and, moreover, inaccessible.

Let me explain a few of these terms, and what they really mean:

  1. Gaussian Blur. All it really means is that someone like me is using an algorithm some guy wrote to blur your image. It’s incredibly difficult to write one that’s fast at all, but that’s my problem.
  2. Unsharp Mask. This is a term borrowed from photography. All it really means is that I blurred your image with a Gaussian Blur, subtracted the difference from the original image and tacked that difference right back onto your image. It’s a lot like that Laz Burhman song. The sliders simply control how much I blur, how much I subtract and how much I add back on.  The bigger differences happen on edges, so when I add the difference back on, I’m adding more to the edges, hence the sharpening effect.
  3. Exposure. It means nothing. That’s why I personally don’t use the term in Sagelight. There’s no standard about what it means, and some editors use it differently than others. There is a trend in the industry to use technical terms to make it seem like we’re doing something more special than we are. In many editors for example “Exposure” just means “it’s brightening your image” (and killing the highlights in the process).
  4. Gamma. All it really means is that it’s brightening your image with a weight on the shadows. I’ll get ostracized in any industry publication for stating it that way, but that’s all it really amounts to in practical terms. It’s important to note that it’s standardized and used all over the place, like on your monitor. A standard curve for RAW files is to perform a curve on your image with a Gamma 2.2., so it’s nice to have a standard so the camera and I can know what to do with your image.

An Old Image Editor.

Well, I could go on. Of course, there are subleties to a lot of these terms that can make them more interesting (and powerful).  But even for me — the author of an image editor — their practical application, at the image-editing level, is that my internal sense of a Gamma Curve (for example) is that it’s going to brighten my shadows more than the rest of the image. As much as I wish I was, I’m not one of those guys that can do the constant formula of some value to the power of 2.19383 in my head while I’m using a slider.

It’s a gut-sense that we get out of these things. That’s why it’s just really about experimenting with enough of a knowledge base to turn the trial-and-error approach into something that’s more intuitive down the road. This enables us to do more in expressing ourselves artistically and creatively — without having to know the science.

Part 2 coming soon…



6 thoughts on “Rule 1: If it Looks Good, then it’s Fine (part 1)

    • Thanks. I was having more fun than I thought breaking it down. I think I might just keep going and adding more and more. I’d like to break such terms into their practical component like the Gamma Curve, for example, (i.e. it makes your image brighter or darker from the shadows) and get more into the specifics about where they are used more precisely.

      Any other terms of interest out there?

  1. Very interesting, but I have two questions:

    Does Sagelight ‘do layers’? If not, how does one preserve the original and save edit-stages from start to final product?

    Can it handle psd files?

    • The idea in Sagelight is that the masking and the Undo Brush (i.e. history brush) make up for 90% of most things you’d want to do with layers (you can load previous history states and snapshots to work with the history state buffer). So, Sagelight doesn’t currently handle layers, but uses them (so-to-speak) in specific functions such as Vignetting, Gradient, etc., and flattening them on the way out of the function.

      It depends on what you want to do. For instance, if you use layers to save every single history state, this adds a lot of time to to the editing process, and this is something I’ve specifically avoided in Sagelight.

      Sagelight is going to support layers in version 4. But, I am taking a longer approach because simply adding layers at they are used in the industry, I think, would make Sagelight much more complicated and put it in the realm of Photoshop, Gimp, etc. I’ve been trying to stay away from that, and am going to add them in a way that keeps the simplicity and adds the power that layers provide.

      I’m looking at layers as a more integral process, using a reverse approach to make layers seamless so that you only use them when you recognize the need sometime in the process, as opposed to having to consciously start a layer at each level.

      Sagelight doesn’t handle .PSD files, but does handle 48-bit tiff files.

  2. “Sagelight doesn’t handle .PSD files”

    So when someone sends me a psd file would I have to convert it to a jpg file BEFORE Sagelight can view/edit it?

    • Sorry for my delay in replying. I lost some program data and had to spend time dealing with that.

      You can also convert it to a 48-bit .tiff or 24-bit.bmp. I wouldn’t recommend converting it to a .jpg, as since if someone is sending you a PSD without doing the courtesy of converting it to a more transmissable .JPG, there’s probably a reason behind it. Of course, by converting it, you’re probably in a program that’s going to let you see it anyway. 🙂

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