Posterizing

[Richard Budig]

Here's a way to sort your photographic, or other source reference material, into three or four simple values. Use the IMAGE -> Adjustments --> posterize menu. I use Photoshop Elements. Don't know about Photoshop. Using this function will translate your photo into a few clumped values. Not too good for detail work, but it will give you an idea of the value pattern(s) in your source material.

You can tweak it a bit to increase or decrease the values and areas of differing values.

Finally, if I'm covering old ground, I apologize.

And, if I knew how, I would delete this message, or the one below it. Me and my computer were going round and round, and I didn't realize I posted twice. Sorry.

[Chris Saper]

Richard,

I think posterizing can be a very useful tool, as well. I find it is much easier for me to interpret if I posterize a gray-scaled image, as posterized color is confusing.

The caveat in posterizing is that it cannot correct value compression that already exists in the image, particularly if its origin is in film, as opposed to digital. Instead it will only accentuate any distortion in values that is already there.

[Richard Budig]

Chris:

Thanks for the comment. I agree, but want to ask you to clarify what you mean in reference to clumping it it's origin is film as opposed to digital.

I think I know what you mean, but could you expand on this a bit, please.

If I understand correctly, the difference is (or could be) that film has been "processed," and comes back to you as a "finished product," in that it has been transfered from negative to photo paper, where yet more "clumping" takes place.

I'm still in the learning curve on digital photo work, but it seems to me that since digital cameras have already translated the image into digital language, which is dumped into a computer that can read the language, and then brought up in a photo processor, such as photoshop, the image can then be further tweaked, including the darks. That's probably "guy-speak" for you can deal almost independently with the lights, middles, and darks in an image that comes to you in digital form.

This is getting more detailed that I meant it to be. Sorry. But, yes, finding a way to view the "big shape" patterns, such as posterizing, can be a help. Also, it seems to me, that you, the artist, can arbitrarily assign new values to the posterized values. For example, if the posterizing process (in gray scale, or b&w) gives you very dark darks, you can, if you wish, choose to bump everything up a value or two, but still use the posterized image as a guide to where your big shapes are located.

Am I thinking right about this?

[Brenda Ellis]

I tried the posterize trick in photoshop and it really does help seperate not only values but clues to possible colors to use. Here is the palette that I digitally picked out of the posterized image for the portrait I'm currently working on. They are all very warm if you ask me and I will probably end up using blues and greens to cool things off in places. But I think this might be helpful for those of us who are still learning to see colors in skin. Guess I'll find out how helpful it is for me!

[Richard Budig]

Brenda:

Yikes!!! How did you arrive at these colors? Did you arrive at them from image converted into black and white, or from the color image?

I would say you certainly have a fair range of flesh tones from which to work, and yes, you'll probably have cool some of them a bit, or gray they out here and there.

Again, how did you arrive at these? Do you use Photoshop?

[Brenda Ellis]

I first posterized the image. Then I created another document with just a white background. Then, I used the dropper tool and clicked with it on a color in the posterized image. That turned my "palette" to that color. I then went to my new document and created a square with the marquee tool, and used the paint bucket to fill that square with the color I had picked out of the posterized picture. I did this with every color I could see in the face and hair (except for obvious blacks and except for the eyes.)

The thing I don't know is how Photoshop arrives at those nine or so distinct colors from a photographed face. They very well may not be what I would want to use to recreate a painted image of the face in the original photo. If you zoom in on a photo in Photoshop or any digital program, you will see that many times, each pixel is a different color that, when zoomed out optically mixes to make the color on that particular thing in the photo. This is why for me it's been a challenge to get my colors from a digital image, because pixels don't act like paint; they display color differently than we do on canvas, so when I look closely at a color, it's hard to tell just what that color really is because it's a bunch of various colored pixels.

I hope some of that made sense. I have Photoshop 7 which I use a lot as a scenic designer. I think, however, that Photoshop Elements has those same tools that I mentioned.

Like I said, I don't know how really helpful those colors will be since the process of posterization is different from the process of mixing paint.

Thank you for suggesting it, though. By posterizing the colored image, I could actually see the various values as well as the discreet color areas.

[Brenda Ellis]

And yes, I used the colored image!

[Chris Saper]

If I understand correctly, the difference is (or could be) that film has been "processed," and comes back to you as a "finished product," in that it has been transfered from negative to photo paper, where yet more "clumping" takes place.

Film photos are made my exposing light to layers of emulsion on the photo paper. DIgital images work with pixels, and there is not as much value compression.

Yes, you can definitely tease out information both in lights and darks with digital images - which isn't the case with film.

Brenda, I am certainly in the slow learner's group with Photoshop compared to you! Having started out with painting from film-based photo images, I still continue to assume that the color will be wrong,the values will be incorrect and that the edges are completely false. I still make those assumptions even though I now use digital images. From my sense of time utility, I don't really try to get the color I owuld get from life, because I don't think I can. (Although Bill Whitaker regularly produces spectacular color in his subject photos)I just try the best I can to interpret what's in front of me.

Posterizing can be a helpful tool, but it's just not the answer.

[Richard Budig]

Brenda, Chris -- thanks for your comments.

Brenda, you say that your eyedropper used the color from one pixel, and that you use Photoshop. I use Phototshop Elements, a slightly stripped down version of Photoshop. However, in Photoshop Elements -- and I'll bet it's this way in Photoshop, also -- you have an option to sample one (1) pixel, nine (9) pixels or twenty five (25) pixels when you click your eyedropper anywhere inside your image area.

In Photoshop Elements, when you click on (select) your eyedropper, a little box appears in a "task bar" just above where you find your eyedropper. It shows a small, square picture of your eyedropper and a drop down menu. This drop down menu lets you decide whether you're going to sample a "point sample," which is just one pixel; 3X3 pixels (9), or 5X5 (25) pixels.

If you choose the 3X3 or the 5X5, you will be selecting an average color from the larger pixel area. This is a nice feature because, as you say, each pixel in a digital picture is one color, and one color only. So, if you happened to land on the only green pixel in a field that seems to be red, you'd be in trouble. But, you would be alright if you had used, say, the 5X5 (25 pixel) sample.

Hope this makes sense. Surely, Photoshop has a similar situation in which you can choose how many pixels you are going to sample.

Note: I just discovered that Photoshop also allows the same sampling options. Just look straight up to find the "task bar" where the drop down menu appears.

[Brenda Ellis]

Ah! Thanks, Richard. I haven't come across this little menu bar. When I click on my dropper, no bar comes up. I'll try double-clicking. I still am cautious about trusting whatever color that dropper comes up with. But it gives me a good idea of the range, I think.