Photoshop Color Separation

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liamrite
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Photoshop Color Separation

Post by liamrite »

I have a client that wants a photo to be screen printed on a t-shirt. I haven't ever actually tried this yet. It looks do-able, since I can print the different color channels in Photoshop (either RGB or CMYK). Seems like RGB would be better since it's less colors, one less screen to burn, right? And will it work if I am using an inkjet printer to print the different colors, or do I need something fancier to make sure the half tones are perfect? Are the key factors image resolution, mesh count, registration? What mesh count shoud I use?

Thanks,
Bill
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Photoshop seps

Post by crowflite »

Whoa there Bill. Yer getting deep fast. There are several things you didn't mention which need to be considered for prep of this proposed order: shirt color, quantity, size....

To start with NO you cannot print from RGB. RGB is a distinction for light source viewing ie; a monitor. RGB seps are not intended for print applications. CMYK is what you will want to print from. Even starting from there there are factors to consider. Just seperating in Photoshop & running out film will probably not result in the a desirable print as the default settings are design for offset print not serigraphy on textiles. textiles act as a sponge soaking in the ink spreading the original intended dot larger. hence you will experience a 'dot gain' of about 15%. In other words an intended 5% dot could result on the teaxtile to a 20% dot. Mesh count & squeegee pressure play into this.

So that's just to start. As complicated as this process is your best to do 200 shirts or more......and that's on white. If you are printing on darks you are into a whole new game: a different program to sep from, printing white, etc. If the quantity is small enough doing transfers would be a more cost effective process. There are papers that accept color print-outs, which you print in reverse, and iron-on to your garment.

This is just a start. You may want to consider a pre-press service to get your film done. They can inform you on the standards for printing full color images.
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Post by SPD »

If you need to print a photographic image, you should make Spot or Process separation.

Spot color separation (simulated process) - you need to create the Spot Сhannels for each color.
CMYK - (four color process) is not traditional CMYK that is used for Offset printing.

Color separation is difficult process, therefore it is necessary to use color separation software or service bureau.
For printing use 305 meshes and 45lpi (45lpi up to 65lpi)
More info: Color Separations
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ROADSIDE
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Post by ROADSIDE »

lol....

Thats funny.... I remember when I asked someone a question similar to this one. I never actually got an answer. I had to READ AND READ AND READ
.... I can give you my opinion but I can't tell you if it's right or not.
SPD
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Post by SPD »

You can easy make color separation into Photoshop if your image has solid colors, but if you wish to make color separation of photo-realistic image, you should develop algorithm for addition and subtractions of colors, also it will be very difficult to make white base for dark t-shirts.
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Post by Maxie »

Does anyone know the color settings for Photoshop CS when printng seperations?
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corradomatt
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Post by corradomatt »

If you are trying to learn color seps in photoshop, there is a pretty good book out there called Photoshop 7.0 for Screen Printers. It gives lots of tips and tricks on many different types of screen printing separations and talks about the differences between spot, sim-process, index, and process seps. It also comes with a CD packed with samples files for all of the tutorials in the book. There is a starter file, so that you can do the tutorial, and a completed file so you can compare your work with that of the author's.

Screen printing separations are truly an art form all by themselves. Even with separation software you should have a basic understanding of how to separate artwork. The automated software will take care of 80% or more of the work, but there is almost always tweaking that needs to be done before the artwork is ready.

Good screen printing begins with well separated artwork. Anyone can pull a squeegee. The artwork makes the print.

Oh, the book again is Photoshop 7.0 for Screen Printers by Joli Ballew. There might be a newer version out now, but the techniques should carry right over to CS and CS2.
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