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Subtle noisy halftone pattern


Jamous

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Hey again guys!

Just wondering if anyone could advise here. Been mucking around with halftones today, saw this image posted somewhere previously with the author claiming it was a halftone. From my understanding the halftone patterns look more "honeycomby", made up of lots of gridded dots - this to me looks a lot more abstract, more subtle, maybe a bit noisy and I kind of prefer it. The subject matter here is crumpled paper if that helps - but I'm at a loss to figuring out what's going on here.

Higher contrast and halftone filter?

Thanks in advance all :)
 

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ALB68

Dear Departed Guru and PSG Staff Member
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I'm not telling you how to do your project, but this screenshot is of true halftoning. This happens to be part of a job I am doing presently for a client that is for screen printing. Notice that this one has an elliptical shaped dot. This was created by specialized printing color separations software. Just FYI
halftone.PNG
 

Tom Mann

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Jamous - It is indeed a halftone image, but not the ordinary kind where the dots are on a regular grid. This approach is called "stochastic halftoning" (Google it - it is very important in the printing industry).

In this approach, the probability of a dot at any position is controlled by the tonality at that position, and the positions are determined semi-randomly by an algorithm, eg, "place more random dots in areas with mid tones, ie transition areas between very light and very dark areas in the original".

Software to do the above can be pricy, but a very good approximation can be done by programs such as VanDerLee's Halftone . Instead of doing the process described above, it first constructs a regular half-tone image, and then randomly moves each dot around within a prescribed radius. If you have a high enough dot density, this approach can look almost identical to true stochastic halftoning.

HTH,

Tom M

PS - The big blocks of solid color are no big deal, you can set the adjustments in most of these programs so that at maximum density the dots completely overlap, and at minimum density, there are no dots.
 

IamSam

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Nice tutorial Larry, gave it a shot........

Screen Shot 2015-04-05 at 1.25.39 AM.png
 

Tom Mann

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I'm sorry if this comes across as me being a curmudgeon, but I've run into that tutorial b4, and I must confess that while the tutorial itself is well done, I have a pretty serious problem with the technique it demonstrates:

Because this technique relies entirely on the dissolve layer blend mode, every halftone dot will be exactly one pixel in size, whereas, in actual practice, one often (almost always?) wants to be able to freely adjust the size of the dots, their size variability, and their average density for exactly the same reasons one might need to adjust the linescreen frequency, angles, etc. in a conventional (ie, periodic) halftone image. To see why the limitation to 1 pixel dots might be important, just try down-rez'ing Sam's image, say by a factor of two. All of a sudden, the discrete dots start to blur into a contone image, which may be utterly useless if you want to print the image, or want the effect to be visible at other resolutions (without re-doing it from scratch at each resolution).

The limitations of this technique for producing stochastic halftones are even more obvious if one is trying to create something like a Lichtenstein: Ben-day dot effect except with nice big, circular, dots that are randomly placed.

I understand that the tutorial "is what it is", and does indeed do what it sets out to do, but I feel that it gives a very limited view of stochastic screening to newbies, and the technique's limitations are far too severe for more knowledgeable folks.

//Curmudgeon mode = off

Tom
 
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ALB68

Dear Departed Guru and PSG Staff Member
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Just something that came up with a Google Tom. I never took it serious for one minute. It's not the real thing but I thought the effect and the way he did it was pretty cool. Although it was a bit confusing at times.
I, not being a master of the English language like you, I had to look up curmudgeon..": a person (especially an old man) who is easily annoyed or angered and who often complains" is quite accurate.:rofl:
 

SCTRWD

Power User
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I'm sorry if this comes across as me being a curmudgeon, but I've run into that tutorial b4, and I must confess that while the tutorial itself is well done, I have a pretty serious problem with the technique it demonstrates:

Because this technique relies entirely on the dissolve layer blend mode, every halftone dot will be exactly one pixel in size, whereas, in actual practice, one often (almost always?) wants to be able to freely adjust the size of the dots, their size variability, and their average density for exactly the same reasons one might need to adjust the linescreen frequency, angles, etc. in a conventional (ie, periodic) halftone image. To see why the limitation to 1 pixel dots might be important, just try down-rez'ing Sam's image, say by a factor of two. All of a sudden, the discrete dots start to blur into a contone image, which may be utterly useless if you want to print the image, or want the effect to be visible at other resolutions (without re-doing it from scratch at each resolution).

The limitations of this technique for producing stochastic halftones are even more obvious if one is trying to create something like a Lichtenstein: Ben-day dot effect except with nice big, circular, dots that are randomly placed.

I understand that the tutorial "is what it is", and does indeed do what it sets out to do, but I feel that it gives a very limited view of stochastic screening to newbies, and the technique's limitations are far too severe for more knowledgeable folks.

Tom


Agreed...

I've always wondered why Adobe never introduced stochastic rasterizing in their products...
 

IamSam

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I understand that the tutorial "is what it is", and does indeed do what it sets out to do, but I feel that it gives a very limited view of stochastic screening to newbies, and the technique's limitations are far too severe for more knowledgeable folks.

Tom

Agreed.

SCTRWD said:
I've always wondered why Adobe never introduced stochastic rasterizing in their products...

Also agreed.

???????

test_01.png
 
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Tom Mann

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SCTRWD - It's beyond me, as well. I've had junior (undergraduate) students write code in Matlab to simulate stochastic screening as an exercise in applied random variables, and it was perfect for their ability level, so obviously Adobe could include it if they wanted. I guess the real question is why don't they want to include this? Worry about feature bloat? A perceived lack of interest in something this specialized? etc?

Tom M
 

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