Some new ideas from Dan Margulis
rutt
Registered Users Posts: 6,511 Major grins
Dan spoke at the CS department at M.I.T. last Wednesday and I learned that he has been trying out some new ideas. I've was inspired by this and by some recent dgrin images to play with these ideas. So, here is a summary of some of those ideas and some examples (with apologies) of recent dgrin postings with some of these ideas applied.
Theory Since this was an academic talk and since Dan is a theorist, he connected his new ideas to famous color theorists.
So much for theory. What about application. Dan presented a new workflow:
So how does this work out in practice? I played with two images I found on dgrin.
Here is an image by Wolfejm from a Whipping Post post.
I processed Dan's new workflow:
Without Leonardo's insight, it looks more like:
Perhaps a blend of these two versions would give the best realistic result?
But Dan showed something else I liked. He used the HIRALOAM layer at near full opacity and the PS brush filter to show just how close to impressionism the workflow has come.
In the spirit of fun, I couldn't help but try this out on another recently posted image (deepest apologies to Andy.)
Theory Since this was an academic talk and since Dan is a theorist, he connected his new ideas to famous color theorists.
- Leonardo di Vinci -- Apparently he discovered an idea that darker colors appear more neutral. At the extreme end, this is obvious, but Dan says that Leonardo meant that this loss of saturation begins much closer to the midtones than previously believed. So lighter colors should be much brighter than darker ones.
- Michel Eugène Chevreul -- A French color theorist from the mid 19th century was the inspiration for the impressionists. I don't pretend to understand what this work (Dan and Fredo Durand seem to agree that the standard translation into English entirely misses the point.) Essentially, though, I think that idea is that we like to see purer colors and that our eyes blend them. I'm probably doing a lot of damage to this idea, but think about impressionist (and post-impressionist) painting and this feature: using purer colors without transitions, does stand out.
So much for theory. What about application. Dan presented a new workflow:
- False profile to lighten the entire image with a lower gamma, to pull the shadows into the three quarter tones and flatten in general.
- Convert to CMYK. Steepen the dark end of the K curve a lot to reestablish good rich shadows with better details and less saturation than in the original. Save a duplicate.
- Convert to LAB. Use some contrast and color enhancement technique on a layer. Overdo it. The Man from Mars technique, the standard Canyon LAB steepening technique, or the overlay layer technique from the portrait workflow are all examples of this.
- Use the K channel (from the saved CMYK duplicate) as a layer mask for the color and contrast enhancing step. Play with a curve on the layer mask to control how it protects the darker parts of the image from color enhancement. Flatten and now we have applied the di Vinci part theory. We have more color in the lighter parts of the image and more detail and less color in the darker parts.
- HIRALOAM on all three LAB channels. Do this on a layer and use a much higher opacity than you normally would. This spreads out colors and intensifies them. It's a local color enhancement just as conventional HIRALOAM is a local contrast enhancement. This gives us our Chevreul effect.
- Lower opacity and adjust relative lightening/brightening of this HIRALOAM enhancement. Use LAB blend-if sliders, move to RGB and use separate lighten/darken layers to adjust. Adjust opacity.
- Perhaps blend conventional USM with this HIRALOAM.
So how does this work out in practice? I played with two images I found on dgrin.
Here is an image by Wolfejm from a Whipping Post post.
I processed Dan's new workflow:
Without Leonardo's insight, it looks more like:
Perhaps a blend of these two versions would give the best realistic result?
But Dan showed something else I liked. He used the HIRALOAM layer at near full opacity and the PS brush filter to show just how close to impressionism the workflow has come.
In the spirit of fun, I couldn't help but try this out on another recently posted image (deepest apologies to Andy.)
If not now, when?
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Comments
This time, only 3 channel HIRALOAM:
Before:
After:
The impressionist technique is the same sort of thing. And its great if you are trying to give the bright, pure effect. It's definitely a better way to get the popular oversaturated effect that seems to be in vogue. But if you are going for the look of Rembrandt, e.g., you best look to other techniques.
Duffy
1) I played some with blending the L channel at low opacity into the K channel mask. This tends to even out the transition some. I then tried playing with blending the mask into itself in overlay mode, which is probably similar to using the curves you suggested.
2) I used the mask on the hiraloam. If shadows to mids should be more muted in color ala DaVinci, then they might also benefit by being less pure.
Anyway, this is what I got. Its an interesting technique, with lots of room for playing around. Thanks for posting it.
Duffy
I just made that up, so I don't know if it makes sense.
As to the 3-channel HIRALOAM thing, it definitely isn't always what you want, just the way impressionism and its descendants aren't always what you want. But it's a wow when it hits and I do like the explanation. Now what exactly was it that the impressionists were seeing? I suppose that the memory of a scene isn't at all the same as the scene itself. A lot of detail is lost and color, big shapes, contrast are enhanced in memory.
I also just made that up. I think you need to be fluent in scientific 19th century French in order to read Chevreul in the original and reason about it.
Thanks
Gary
gchappel
Looks good, Duffy, and I like your variations a lot.
Gary
gchappel
Hmm... HIRALOAM on a and b won't cause color shifts, just some spreading/intensification?
Thanks
"It is a magical time. I am reluctant to leave. Yet the shooting becomes more difficult, the path back grows black as it is without this last light. I don't do it anymore unless my husband is with me, as I am still afraid of the dark, smile.
This was truly last light, my legs were tired, my husband could no longer read and was anxious to leave, but the magic and I, we lingered........"
Ginger Jones
The short answer is probably that, in most images, the result is good enough on all three channels at once. But breaking things apart will give you greater control, at the expense of some time.
Duffy