Help! File separation question…

TW
Posted By
Tom_Walace
Dec 15, 2003
Views
1098
Replies
36
Status
Closed
I have a PS file of a "chrome" looking shape. It’s currently full color/cmyk.

I want to separate it into 3 different contrasting values: Very dark, Medium, and white for screen printing purposes.

Of course, when I say dark, medium, and white…I am referring to the eventual spot color inks, so I need to visually separate these tones from the original image, and then be able to ouput them as black of each of the three tones.

Am I making any sense here?

These values need to be knocked out from one another so they don’t overlap, at least not significantly. They will be printed in a diffused dot or stochastic type random dot pattern, and for what we’re doing a "little’ overlap wouldn’t be harmful.

Can anyone explain a way I can achieve this? Please give me a detailed step-by-step if you could, …. I’d sure appreciate any help you could offer. Thanks.

Tom

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TF
Timothy_Foolery
Dec 15, 2003
I’d re-draw it in Illustrator and print it to the film from there. BTW "a little overlap" is called trapping and you will want the white to go under everything remember. A friend of mine uses Photoshop to do his seps, I’ll go ask him if he’ll help.
J
JasonSmith
Dec 15, 2003
"dark, medium, and white"

so that would be two colors – dark and medium, white will be your paper/substrate.

if you want a quick and dirty way, select your ‘dark’ tones, then apply to a Cyan (only) channel. Select your ‘medium’ tones, then apply to a Magenta (only) channel.

Tell the printer/person mixing the ink to print C as Pantone___ and M as Pantone ___.

Or try converting to greyscale mode, then to Duotone mode. select your spots, and adjust the curves as neccesary.
TF
Timothy_Foolery
Dec 15, 2003
Jason "screen printing"…

so that would be two colors – dark and medium, white will be your paper/substrate.

Nah hah. {shaking my head}

He’s also going to have to know about setting his halftones etc. It’s a whole different trailer of squirrels.

My friend has a channel calculation method he might be willing to give a few tips on. Otherwise he might give Tom a run down on some of the basics. I’ve sent him a message, hopefully he’ll be by soon.
SV
Steve_Vesperman
Dec 15, 2003
Tom, if you’re using random dots then seperating the job in index colour is the way to go. You get each colour butt fitting agains each other with no over lap. Only trouble is you don’t get the extent of a single colour feathering out to 0% as far with index, it’a little posterised so more colours are better.

To do the seps in index you have to check the colours you have first. Also you have to set your resolution to the output dpi before converting to index, I use 170 line per inch for screen printing, once you have set your resolution at actual print size (you can’t resize once you have converte4d to index or you will change the resolution or worse), go to image>mode>indexed color.

You now have the dialogue box open, turn off preview and go to pallete>custom, the color table will open, select the bottom right square and shift drag to the top left square, the colour picker is open now if you’ve done that right, drag the selector to the white point in the top left and click OK, do this a second time. You now have a whole file of white squares in the color table.

Click on the top left square and the color picker will open again, When you place your cursor over the image, you can eye drop the colour you want, click OK, select the next square and do the same, whan you have picked the three or 12 or whatever amount of colours you need, you can save the color table, and click OK. You’re now back at the index color dialogue box, turn on preview. If this looks good then click OK, if not go back and tweak the colors under the pallete>custom drop down menu again until you have the right blend working, don’t forget to re save if you do change them though.

Now you have a very grainy looking file, don’t worry, it prints great!

To seperate the file go to your channels pallete and drag the index channel to the bottom of the pallete onto the square that has the paper with the fold in the left corner, this duplicates the index channel. Go to image>mode>color table, and the colours you sellected are there again, click on the squares one at a time and colour pick them to white until you get to the first square which you make black, click OK.

You have a new channel which is just the colour you wanted for that sep, click on the channel, make the solidity 100% and click on the colour square and make it the first colout you selected.

repeat this whole process until you have a channel for each of the colours you have made, turn them all on and viola, you’re ready for film.

Right, that’s index covered, now here’s halftone. With you rgb file open, go to select>color range, and by using the eye droper and fuziness slider, with your selection previw on grey scale and invert turned on, find the first colour you need, click OK, thins give you a selection which you save in select>save selection as a new channel.

Do this until you have all the colours you need, you might like to check eack time in colour range under sampled color for a preset that might fit the bill.

You now have a halftone version, that if you really wanted to you could convert each sep to index and have the dadom dot you desire. I have heard of it but in 20+ years in screen print art I’ve never done it.

That’ll be $500 for for the consultation thanks. 😉
SV
Steve_Vesperman
Dec 15, 2003
I haven’t spell checked or grammar check because that’s the biggest speel I’ve ever writen in my life. 🙂
TF
Timothy_Foolery
Dec 15, 2003
Thanks Steve, I knew you’d come through. 🙂
G
graffiti
Dec 15, 2003
that’s the biggest speel I’ve ever writen in my life

It’s gonna suck when he never comes back to read it. 🙂
SV
Steve_Vesperman
Dec 15, 2003
Oh yeah, thanks mate!!!!
G
graffiti
Dec 15, 2003
Oh yeah, thanks mate!!!!

You’re welcome.

I’d just copy and paste it into a Word document for when he comes back and can’t find this thread. 🙂

P.S. Tom. If you do make it back, no offense intended. Just funnin’ Steve a bit.
TF
Timothy_Foolery
Dec 15, 2003
I’d just copy and paste it into a Word document

Steve = Maccie. I don’t think he uses any M$ products. 😛
SV
Steve_Vesperman
Dec 15, 2003
Graf’s a maccie too, I don’t know what the hell he’s dong here actually, apart from giving me some curry. 😉
TF
Timothy_Foolery
Dec 15, 2003
Bluddee Maccies!! Close the door on yer way out. We don’t take kindly to your type in these here parts boy! 😉 🙂
G
graffiti
Dec 15, 2003
don’t know what the hell he’s dong here actually, apart from giving me some curry

It’s just more entertaining over here. 🙂
J
JasonSmith
Dec 15, 2003
"He’s also going to have to know about setting his halftones etc."

Umm, I take it he doesnt have a RIP?

(hint – you leave that for Harlequin to take care of)
TF
Timothy_Foolery
Dec 15, 2003
Jason, have you done a lot of printing to backlit imaging film to be used for setting screens? He’s probably printing either to a Designjet or to a HP Desktop printer and taping it together on ye olde lightbox.
SV
Steve_Vesperman
Dec 15, 2003
Jason he seems to want to apply the index method to either the greyscale channels or the index ones, either way there are no need for halftones.

If he needs more details on halftone spot colour seps then he should be more specific.
J
JasonSmith
Dec 15, 2003
"have you done a lot of printing to backlit imaging film to be used for setting screens?"

Yes, for 8 years now. Fortunately I’ve had the luxury(?) of a film imager at my disposal.
TF
Timothy_Foolery
Dec 15, 2003
You lucky little poppit 🙂
J
JasonSmith
Dec 15, 2003
I feel sorry for the guy if he has to do it all in P-Shop….I’ve done the PS method a few times just for laughs – when I was bored.
TF
Timothy_Foolery
Dec 15, 2003
just for laughs – when I was bored.

You must have been very bored. <g>

I usually do it all in Illy. Right or wrong it’s what I’ve always done. Most of the crap I get sent has to be re-drawn anyway. {shrug}
SV
Steve_Vesperman
Dec 16, 2003
How can you tell without seeing the image Jason, I do stuff like this everyday in Photoshop with my eyes shut…and it looks like it too. 😉

I separate all my art in Photoshop regardless of where I made it, this one here was vector, then taken to photoshop for finishing and separating. <http://www.acay.com.au/~waylie/freehandmx.jpg>
TF
Timothy_Foolery
Dec 16, 2003
Nice Steve…I hate you <g>

I just make as many copies of the object as there are colors, knockout all the wrong colors in each one and make the one I want black (after labeling everything for the stoopid printers ;))

Then I use a rider file for the halftones (I have to keep it at no finer than 33 LPI for sublimation or our guys can’t seem to blow the dots out)
G
graffiti
Dec 16, 2003
Nice Steve…I hate you <g>

Yeah. Every time I see Steve’s work, it takes me a while to get over my artistic insecurities. 🙂
JS
John_Slate
Dec 16, 2003
While Steve’s indexed color approach is highly commendable, I wonder if simply using the select color-range method with the eyedropper to define the extent of each of the 3 selections, and then filling spot channels with black might also work, and maybe avoid a little posterization.

A slight overlap of the ranges in these Highlight, midtone and shadow selections would not really qualify as trapping, since we would be talking about some areas of superimposed halftone screens. Halftone dots of any geometry do not trap to halftone dots on another plate… they intermesh.

The type of work described here has been done conventionally by old-school printers for years with creative exposures (main, flash and bump) on a process camera with a halftone screen, though the overlap/and/or isolation of tonal ranges could never be controlled the way it can be in PS. A 3-color neutral tri-tone would have been a lot of fun to produce.
SV
Steve_Vesperman
Dec 16, 2003
I offer both options as easy outs for the low/no experience operator John. my first though was a light, mid, dark separation too, but I’m just responding to the question without seeing the art.

10+ years in the dark room here prior to Photoshop too. Channel calculations are my area of expertise regarding colour separation for dark and light garments. Art departments I’ve run have won every screen print award in Australia for my halftone and index work.
TW
Tom_Walace
Dec 16, 2003
Wow! I’m impressed and grateful at the huge response in the handful of hours that went by without checking back in. Let me read through these, catch my breath and get back into this post.
TW
Tom_Walace
Dec 16, 2003
By the way, what’s a "maccie and a poppit"? (i’m sure you’re chuckling now 😉 )

Since the image I want to separate out as described in the original post is a full color chrome item, say a motorcycle exhaust pipe for arguments sake….by using the method you suggest Steve, would this drop out the other colors not selected as the "dark, medium, and light/white"? This would be fine for what I want to do.

After the colors are separated out, I’d like to save each of the three tones as a black bitmap (at full size) and then place them into Illustrator within the vector outline of the shape of the "exhaust pipe"….apply a color to each of these shapes, register them together and "clip" them into the path for printing on an ink jet printer for presentation to the customer…..

These files would also be the basis for the screen printed part once the "look" was approved by the customer. I hope this helps clarify what I’m after…if not, slowly guide me along, as I’m a designer and don’t have a great in-depth knowledge of screen printing. Basic knowledge, but that’s about it.

Sad to say, but I don’t think our screen production artists would know how to do take an image and do what you’re suggesting to make it printable….so this is all good educational instruction for us all. Thanks for your replies…I’ll check in throughout the day. P.S. – – I’m in the US, and it appears you guys might be in AUS? So there will be a big time difference, no doubt.
TW
Tom_Walace
Dec 16, 2003
John, can you also detail you’re suggested method? I’d like to try both. If you wouldn’t mind, can you do it in a step-by-step? No little detail is insignificant, sometimes I’m a little dense. Show me visually, and I’d get it in a snap…but for some reason, I need a lot of detail in the written form to "get it". Haha….sorry for my denseness. 😉
JS
John_Slate
Dec 16, 2003
Go into select>color range.

Use the eyedropper in the image window to select the basic area you want to isolate.

Use the + eyedropper to increase the range of colors selected.

Use the – eyedropper to decrease the range of colors selected.

Use the fuzziness slider to make a smoother or sharper transition to your selected range.

Once you are happy with the black and white preview of the areas that you have defined in the color range dialog box say OK, then in a new spot channel of the appropriate colored ink, fill with black.

Note that you can also make your selection range appear a couple of different ways in the image window by scrolling the "selection preview" field.

You might also try scrolling the "select" field to highlights midtones and shadows, but this offers less control.
P
Phosphor
Dec 16, 2003
Maccie:Maccer::Trekkie:Trekker

Just a grinning elbow nudge-n-a-wink at those of us who know a good, secure operating system when we see one.

😉
JS
John_Slate
Dec 16, 2003
hunh?

wrong thread?
TF
Timothy_Foolery
Dec 16, 2003
John, I think Phos was referring to me calling Steve a Maccie.

Just a grinning elbow nudge-n-a-wink at those of us who know a good, secure operating system when we see one.

Or sentimental types with lots o’ bucks! 😉
TF
Timothy_Foolery
Dec 16, 2003
it appears you guys might be in AUS?

Steve is in Aussie, I’m a Kiwi.

Steve = Screen printing Guru. 😉
TW
Tom_Walace
Dec 16, 2003
Thanks John and everyone….I’m going to experiment with these. If I have troubles…I’ll be back within a couple days. Have a great one.
SV
Steve_Vesperman
Dec 16, 2003
John’s is good advice, keep it simple and you can’t go wrong, I’d been promising Timmy a run down on various screenprint seps methods for ages so this was a good opportunity to get the ball rolling anyway.

I’ll do a little step by step on underbases and halftone work on black shirts and we can put it in the Photoshop lounge repository I suppose.
TW
Tom_Walace
Dec 18, 2003
Thank you again Steve….I really appreciate you sharing your knowledge. I’ll be poking around looking for your step-by-step.

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