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screen printing => Separations => Topic started by: Rocfrog on October 15, 2012, 03:03:43 PM
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I'm the graphic designer for a small screen print shop and am relitivly new to the game (about a 1.5yrs into it) and I have come across this sevral times but have always been able to sort of make it work but there has to be a better way.......
I've been given a raster PNG file that the customer wants to get printed. Normally the art work is pretty bad and I need to recreate it anyway but this one is done very well. So I was wondering how do i go about printing out the seps for spot printing?? I work mainly in Illustrator.
(http://img.photobucket.com/albums/v620/Rocfrog/Art%20work/SpartanLogoNew_zpsbb70b7af.png)
Nick
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Step 1. Boot up Photoshop. (Hopefully, you have it, or it will be step 2.
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Photoshop would be where I'd go in lieu of a vector file. I'd separate this into 4 channels, Black, Blue, Green and Gray. If you don't use Photoshop, then that might have bounced of the front of your head, but there are a bunch of us here that will help you if you like. As I started to say, once I save the 4 channels, and assign each one a spot color, the the file can be "placed" into Illustrator, the the spot colors come in with it and show up in your color pallet.
Steve
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Let's hope that he does indeed have Photoshop, and someone can then walk him through Color range and the marching ants to select each color. That's always good info for anyone new at this.
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Sorry guys I had a few sales people come thru my office and got side tracked.....
Yes I do have Photoshop. I have used Photoshop before for color correction but I have never used it for screenprinting pourpouses...... So I am a complete NOOB when it comes to do any sort of seperation work with that program.....
Oh and BTW I have CS5.5
Nick
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netseps.com
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How to do a Color Separation in Photoshop Part 1 (http://www.youtube.com/watch?v=obh3f-gDm4A#)
May be this might help.
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I'm in a similar situation , new to photoshop.
Any chance someone would do a quick tutorial using this design and seperating to 4 colour ,
You know in your extra time :)
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netseps.com
I don't need someone to do it for me, I can completely recreate it from scratch my self just wondering/looking for a simpler/quicker way. Pluse i have seen tons of people that use Photoshop in screen printing aplications just unsure how it's done....
Nick
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netseps.com. . quit Fkin around. . .just sayin. .
if you could do it, you wouldn't be askin. . .
-totally not trying to be a dick -just trying to save you the trouble/money, so don't take offense.
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OK, Nick, open the png file, then make a duplicate (image menu) and close the original. Now, make sure your "Channels" pallet is visible. With your magic wand tool, select a black section, then go to the Select menu, and choose "Similar". This should select all of your black. In the channels pallet, at the bottom, click on the icon 2nd from the left and and the black will be saved as a separate channel. (Don't worry about it looking like a negative, we'll get to that.) Then I would do the same for the grays, if you don't get all of the gray, then hold your shift key and select the remaining areas of gray, and click the 2nd icon from the left at the bottom of the panel, which will save all of your gray as a separate channel. The next part is a bit tricky, because of the green in the shield fading to the blue, but... Go to the select menu, and choose Color Range. You'll get a dialog box with a preview image and a slider. At the bottom of the dialog box, make sure "Selection" is clicked. With the eyedropper tool that you get when you choose "Color Range" click on the green at the top of the helmet, then move the slider all the way to the right (it'll read 200) and click OK.This will make a selection of the green which you'll save as a channel by clicking the little icon again. Now do that same thing again with the blue, except lower the slider to around 125 or so. Click OK, then click that little icon again, and you now have the RGB channels plus Alpha 1, Alpha 2, Alpha 3 and Alpha 4. Click on any of the new channels, and in the Image menu, Adjustments, and select "Invert". Do this for each of the new channels. OK, you now have your 4 channels, all that's left is to color them, save the file and bring it into Illustrator. Back to your Channels pallet; let's say Alpha 1 is your black; double click on the right side of the channel and you'll get a dialog box about the color; choose "Spot", then click on the chip, which brings up the color picker. Click the "Custom Color" button, and choose a Pantone Black. Click OK and that channel will now be black. For the gray, choose Cool Gray 442 or there about, and click OK. Do the same for the green and the blue. Save the whole damn thing as a Photoshop file, and make sure the "Spot Colors" checkbox is checked. Now go back to Illustrator, call us a blank page, and Place the new file. The 4 colors you assigned will be added to your color pallet. Go to print, and choose which colors you want to print and shut the others off. Whew! Hope this helps.
Steve
There are a few other things to try of course, but this will get you started, plus it shows two ways to choose colors, with the magic wand and with Color Range. BTW, it took 3 times longer to type this out than to do it... once you know, you know, and you get faster.
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netseps.com. . quit Fkin around. . .just sayin. .
if you could do it, you wouldn't be askin. . .
-totally not trying to be a dick -just trying to save you the trouble/money, so don't take offense.
No offense taken, just saying. besides I'm an employee of this company and the owner doen't like to spend a penny so it wouldn't work anyway. I'm always up for learning new tricks and this is one that has been eating at me for some time now. I'm using this job as a learning tool for when I step out on my own.
Nick
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Ok Steve thank you that is exactly what I was looking for! Which worked.....but......the gray channel didn't do any half tones.....only a solid color? And the Kelly picked up a TON from the black.....see screen shots....
Kelly
(http://img.photobucket.com/albums/v620/Rocfrog/Art%20work/Kelly_zps383ba333.jpg)
Gray
(http://img.photobucket.com/albums/v620/Rocfrog/Art%20work/Gray_zpsb98fd564.jpg)
Black
(http://img.photobucket.com/albums/v620/Rocfrog/Art%20work/Black_zpsb840dc39.jpg)
Royal
(http://img.photobucket.com/albums/v620/Rocfrog/Art%20work/Royal_zpsa334bc64.jpg)
Nick
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I would go back up and watch the video that Abchung put there. I didn't follow Steve's writeup. Not that it's bad or anything. Just that I'm more of a 'visual" guy.
To get halftones, instead of 100% fill, make the fill around 60% (trial and error here) to get the halftones at the opacity you want.
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I would go back up and watch the video that Abchung put there. I didn't follow Steve's writeup. Not that it's bad or anything. Just that I'm more of a 'visual" guy.
To get halftones, instead of 100% fill, make the fill around 60% (trial and error here) to get the halftones at the opacity you want.
It was visual in my head, or maybe it was a sixties flashback. I did leave a part out, of course. Regarding the gray, in your channels pallet, select RGB (that will highlight those channels). On a Mac, hold the Command key (Alt on a PC? or Control?) and click on your Gray channel; this will make a selection, see the ants, and "copy" from the RGB, then select your gray channel, with the ants still a-marching, and paste; there are your tones. Sorry I left that out last night. And do look at the other tut posted, in fact, look at as many as you can find; you'll develop a nice toolbox that way.
Steve
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Thanks guys for all the GREAT help!! I will tinker with this some more later on today and see what I come up with. I have been trying to find tutorials on how to do this for sometime now and this is a step in the right direction! I will watch the video (once I'm on a computer with sound) and see if i can find more, like screenxpresssaid I'm also a very visual person. Sbrem I had to print out your instructions so I could follow along and not get lost and even then it took me sevral times to get it right, also kept getting interupted by the printers and the phone.
Nick
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Here are some that I found helpful. He has a mini series of them to learn from.
Eternyl Quick & Dirty Photoshop Sep Tutorials - The Underbase Film (http://www.youtube.com/watch?v=186Nz2erRgw#ws)
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We are printing this today.....if all goes well I'll post some pictures of it! Thanks again for all the GREAT info!!
Nick
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Here is the pre-test pellon.....
(http://img.photobucket.com/albums/v620/Rocfrog/Screen%20Printing/IMG_4387_zps6717e765.jpg)
Nick
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Not bad. The only thing different is the tones of gray. Did you use a gray or did you print black? I see a smidgen of shade in the sword but very little. What line screen halftone was used? even the small shading you have, looks very fine. Maybe it was too high of a line count? Not sure.
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Here is some pics of the test print on a shirt. FYI these are crappy cell phone pics....
(http://img.photobucket.com/albums/v620/Rocfrog/Screen%20Printing/IMG_4388_zps1d240cdb.jpg)
(http://img.photobucket.com/albums/v620/Rocfrog/Screen%20Printing/IMG_4389_zps7f085bcd.jpg)
(http://img.photobucket.com/albums/v620/Rocfrog/Screen%20Printing/IMG_4390_zps29e97087.jpg)
Not bad. The only thing different is the tones of gray. Did you use a gray or did you print black? I see a smidgen of shade in the sword but very little. What line screen halftone was used? even the small shading you have, looks very fine. Maybe it was too high of a line count? Not sure.
We use our standard gray to print the gray, this is all hit flash hit...no wet on wet. For the half tones I use 55lpi and 22.5angle...this is just what I've been told to use. This ended up being a 5 color print, white undelay, grey, flo green (custom mix), royal, black.
Nick
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Ok. These pics look much better. That first one was miss leading. This isn't bad at all. What was the mesh used fort he 55 lpi? It's possible some smaller dots were lost but it's common. For halftone dots at 55lpi, you should be using a 230 mesh at minimum or a 305 mesh. THis helps assure that you stand the best chance of holding the smaller dots. It works on the mesh best. People like to use 4.5 as the magic number to help determine the best mesh. I even use 5.
230 mesh divided by 4.5 = 51.11 line screen (rounded to the nearest) = 50 lpi.
230 mesh divided by 5 = 46 line screen (rounded to the nearest) = 45 lpi.
305 mesh divided by 4.5 = 67.77 line screen (rounded to the nearest) = 65 lpi.
305 mesh divided by 5 = 61 line screen (rounded to the nearest) = 60 lpi.
You are learning from this one, but what would have made this more dynamic is to also include a % (10-15%) of black halftone for deeper shading on the darker parts of the gray also.
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I think all but the black is on a 305 screens. I agree this print could probably be 100 times better but with our sub-par equipment (exposure unit) and this technially should have been printed as a 3 color (drop the white underlay and the black), I think it came out GREAT!!
You are learning from this one, but what would have made this more dynamic is to also include a % (10-15%) of black halftone for deeper shading on the darker parts of the gray also.
We print half tones all the time, the learning process for me on this one was to figure out how to print our of Photoshop. Now do I know how to create AMAZING half-tones....no way! Like I said before our sub-par equipment and my limited knowledge is holding us back. To print out my seps I print out of Illustrator into an Adobe Post Script file and then open that up in GhostScript View and then Print to a non-postscript printer (Epson WorkForce 1100), the only thing I do to it is when selecting the spot colors to print I change teh LPI to 55 and the Angle to 22.5 because that's what the previous artist did here.
Not sure using the steps layed out for me above how I would acchive the "black halftone" your are talking about.....???
EDIT: sorry I just reread this and it sounds defensive......I meant that in no way, just trying to give you an idea of our current process and my limited knowledge. I was thrown into a very lo quality shop with ZERO screen printing experiance and the "printers" have little to no experance as well...
Nick
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No Prob. Been there, done that and got a few tee shirts. LOL.
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What about the fade from green to blue on the shield?
I know when I played with the file I had the same issues... I used some tricks to include it but still didn't like the results... but I didn't need to print it and had to leave so I stopped playing with it.
Overall it looks like a great job!
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You could take your gray channel, duplicate it (gray copy) then using curves, reduce that down to only the very darkest parts. Then, you combine that "new" gray channel, with the black channel using "Calculations" under the Image menu, which will give you a new channel that has your original black and the altered gray information, putting a little shading in your grays too add depth and form. You use this new Black instead of the old black, delete that old black channel. As you move along through this stuff, you're going to find "Calculations" to be very useful.
Steve
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It would be interesting to see your process in calculations. I only use them to pull unique colors on occasions. Maybe you have something to add to my process.
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What about the fade from green to blue on the shield?
I know when I played with the file I had the same issues... I used some tricks to include it but still didn't like the results... but I didn't need to print it and had to leave so I stopped playing with it.
Overall it looks like a great job!
What about the fade? yes it didn't go all the way across like it should but if I selected mor color then it grabbed the surrounding in the black as well and I didn't want that.
Thanks I think it turned out "ok".....
You could take your gray channel, duplicate it (gray copy) then using curves, reduce that down to only the very darkest parts. Then, you combine that "new" gray channel, with the black channel using "Calculations" under the Image menu, which will give you a new channel that has your original black and the altered gray information, putting a little shading in your grays too add depth and form. You use this new Black instead of the old black, delete that old black channel. As you move along through this stuff, you're going to find "Calculations" to be very useful.
Steve
ok....wow...you completely lost me.....not that that is hard to do..... ;0)
Nick
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Sorry about that Nick, I know it's a bit much. I sent Dan an explanation, maybe he can post it for me, I gotta get outta here right now. I'll check back.
Steve
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Attached is the image that Steve (Sbrem) created from calculations for those interested.
He sepped out the black (Alpha 1) and the Gray (Alpha 2), then made a dupe of the
Gray (Alpha 2 copy) then did the calculations for the new black channel (Alpha 3).
Also, my settings in the Calculations dialog box...
This gives you the shadows areas to add to the black screen to add to the depth of the image.
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sorry guys I tend to get sidetracked easily and forget about posts soemtimes....
I think I somewhat understand what's going on here....I'll have to tinker with it some...
Nick
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While my understanding of all the possibilities of calculations is limited,
The only ones I really bother with ( thanks to an old post by Steve V )
do little more than 'select part of a channel and add/subtract from another'.
Having said that, I'm still monkeying with a seperation prepping thing.
Calcs make for a much cleaner looking action script.
Just be aware that most calcs are just a reproduction of what you'd do 'by-hand' when sepping.
Like..instead of picking a channel, making a selection, selecting and/or duplicating another channel,
then adding/removing the selected data from it, etc.
All meat and potatoes one needs to understand in any piece of software.
Once you get that stuff figured, calc away.
Photoshop is fairly straight ahead.
You'll get it all figured if you use it enough for awhile.