Author Topic: CMKY Channels print in grey? (Read 1041 times)

SBrem · « **Reply #15 on:** February 21, 2011, 02:55:43 PM »

I think maybe you are missing a lot of information you need to know to do CMYK. The way you word your questions makes me think that, but here goes... As said earlier, each channel is represented as a single black and white picture. This is what you need to make a film, after all, just like spot colors, your films are black and white (clear in place of white). You need one each for C, M, Y, and K. If you split your channels, (Channels pallet, options menu, "Split Channels") you'll then have 4 separate files representing a grayscale of each the 4 colors. To convert to halftone, save a COPY of each of these, then convert the mode from grayscale to bitmap. In the following dialog box, increase your output resolution to about 1200 (this will make for cleaner dots) and change the Method to Halftone Screen. In the following box, set your line count, angle and dot shape and click OK. View it at 100% to see the dots cleanly, and print it out on paper to get a look.

Steve

knowing how to get to CMYK from RGB is another story altogether, and that comes before the above technique.

BigmanJames · « **Reply #16 on:** February 21, 2011, 03:23:11 PM »

Thanks Steve, I saved one of the channels(in this case Magenta) as a PDF file. When opening, go to change the mode into Bitmap.
A dialog box then pops up i set the pixels to 1200 per inch like you said. Now there is another field on the dialog box which says
Method Use. I am guessing to choose the default 50% Threshold(which worked nicely), but there are
also other choices.

Are these new bitmaps(transparancies) now simulating CMYK or are they true CMYK? Are the pigments now going to split a pixel(hence 50% threshold) or will the still overlap each other to form different colors?

Thanks for explaining the bitmap process.

JBLUE · « **Reply #17 on:** February 21, 2011, 03:50:36 PM »

Quote from: killergraphics on February 21, 2011, 01:53:30 PM

I can't see that.

But my question is can you still set dpi, angle and dot?

Jason
I like your site. Nice colors.

Johnny

Thanks. It was something I threw up real quick 2 years ago. I need to go in and edit it. Just been to busy printing to mess with it. One of these days though.

SBrem · « **Reply #18 on:** February 21, 2011, 04:23:41 PM »

Quote from: BigmanJames on February 21, 2011, 03:23:11 PM

Thanks Steve, I saved one of the channels(in this case Magenta) as a PDF file. When opening, go to change the mode into Bitmap.
A dialog box then pops up i set the pixels to 1200 per inch like you said. Now there is another field on the dialog box which says
Method Use. I am guessing to choose the default 50% Threshold(which worked nicely), but there are
also other choices.

Are these new bitmaps(transparancies) now simulating CMYK or are they true CMYK? Are the pigments now going to split a pixel(hence 50% threshold) or will the still overlap each other to form different colors?

Thanks for explaining the bitmap process.

After setting the resolution to 1200, change the Method to Halftone Screen, then to your linecount (this is how many dots per inch in the halftone, say 40 or 50 for t-shirts) your angles, all at 22.5? (for now, be patient) and the shape to Ellipse. You'll see after you do this... BTW, I save as .tif files before I convert from grayscale to bitmap.

BigmanJames · « **Reply #19 on:** February 21, 2011, 04:52:18 PM »

Steve,actually im going to be printing art prints, not shirts. So using 230 mesh. A good rule of thumb I read online is to divide your mesh by 4 so am guessing my LPI at 45 should work well.
I learned alot from the Wiki entry here:

http://en.wikipedia.org/wiki/CMYK_color_model

Really prefer CMKY because you can attain just about any colour.

Now I will have to score some process inks online and get this idea onto paper!

Frog · « **Reply #20 on:** February 21, 2011, 05:03:32 PM »

Quote from: BigmanJames on February 21, 2011, 04:52:18 PM

A good rule of thumb I read online is to divide your mesh by 4 so am guessing my LPI at 45 should work well.

Actually, the mesh number usually given is 4.5 times the line frequency (or vice versa), and 5 times is even safer to reduce the possibility of moire interference patterns between the "grid" of the dots, and the "grid" of the mesh. You are pretty good with your 230/45
Angle comes into play here as well.

SBrem · « **Reply #21 on:** February 22, 2011, 07:30:50 AM »

Quote from: BigmanJames on February 21, 2011, 04:52:18 PM

Steve,actually im going to be printing art prints, not shirts. So using 230 mesh. A good rule of thumb I read online is to divide your mesh by 4 so am guessing my LPI at 45 should work well.
I learned alot from the Wiki entry here:

http://en.wikipedia.org/wiki/CMYK_color_model

Really prefer CMKY because you can attain just about any colour. Actually, CMYK produces less colors than you can see. For instance, CMYK cannot reproduce fluorescent colors...

Now I will have to score some process inks online and get this idea onto paper!

I like Union's Tru Tone inks, plus you can get a color profile from them to put into Photoshop so when converting from RGB to CMYK, PS will know the values of your inks.

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Author Topic: CMKY Channels print in grey? (Read 1041 times)

SBrem

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BigmanJames

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JBLUE

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SBrem

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BigmanJames

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Frog

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SBrem

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