I've been doing a little reading on this and it sounds interesting. Is anyone here doing it? From what I gather, you print CMY and K colors, each in half tones and the end result looks close to the original photo.
I read that you need very, VERY precise registration and fine mesh screens (300 or so). All I currently have are 110. Are there any other tricks? Do you have to thin the ink using a fine mesh screen? I would be printing on transfer paper, not directly to the fabric.
I've done some screen printing, but since I set up to do digital transfers, I haven't even looked at my screen printing equipment. This whole dark shirt thing has me wanting to blow the dust off it though.
There are some videos on 4 color process that you should watch before you start this.
I have one video that watched recently that convinced me that I was not ready to dive that deep into the craft.
Yet, it was fun to watch how it worked.
__________________ Insanity is when you keep on doing the same things, hoping for different results.
There are some videos on 4 color process that you should watch before you start this.
I have one video that watched recently that convinced me that I was not ready to dive that deep into the craft.
Yet, it was fun to watch how it worked.
Online videos? From what I can gather, registration is a pretty big deal, especially if you're using high frequency halftones. Other than that, I don't see it being that difficult. Creating the 4 color separation films in X3 isn't hard. I've printed 4 colors before, just not process CMYK. I figure it will cost me 4 screens, 4 quarts of ink and an afternoon to give it a shot.
I'm currently in the process of perfecting my ability to print process color. So far things have been going well. It has taken at least 6 sets of 5 screens to get me to where i'm at now and expect to go though more screens in the future. I'm glad to share whatever knowledge i have.
Probably the most critical aspect if process color is the exposure. I'm using a vacuum frame and a used commercial exposure setup. Only with a great exposure setup is it possible to make great halftones.
Nearly equally as critical is having a good positive to burn into the screen. I use a postscript laser printer and print on kimodesk transparencies. Inkjets can work just as well.
For ink i use Union ink plastisol CMY inks, but generally use a good spot black ink for the K. For white underbase i'm liking unions cotton white.\
For screens i use 305 mesh for the CMYK and 110 mesh for the white underbase and the optional clear overprint.
For output i use adobe photoshop and print out using adobe default screens for 55 lpi. Adobe screens are slightly different in angle and line value than the traditional angles.
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Separate from the mechanical aspects of printing process color, there is also a calibration process. For this i use adobe photoshop's transfer function in the print dialog. These are the magic numbers which makes everything work correctly.
In me case, i'm calibrating my transfer to allow a double squeegee action for each color. Rather than depending on a single squeegee action to lay down a 100% perfect image, i use 2 actions which when averaged together form the final image.
Registration is the easy part. Either you have a press which can be registered and hold register or you don't. Process color is no more demanding that a multi color spot job. All of the registration marks need to stack over each other. The amount of trap on the white is probably the most significant registration point.
Printing on transfer paper is coming up soon on my list. From my limited experience, i believe that a transfer should come out looking better than a direct print, since a direct print is effected by surface defects, where a transfer is printed on a perfectly flat piece of paper which is pressed over the surface defects. When screen printing over a bump, the bump effects the color, but i would think that if a perfect image were pressed over the bump, the result should just be a bump.
Anyone have a recommendation on transfer paper???
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Personally, i believe Adobe Photoshop is essential to the production process. If you don't have it, buy it. If you can't afford it, buy an academic copy. Photoshop is the simplest way to make the white channel.
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Postscript printer or rip. While not 100% requires, process color is already hard enough, no need to make it a lot harder.
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From the amount of fear process color printing evokes in many screen printers leads me to believe that there should be a market to screen printed process color. I also believe that there are good reason why screen printers are afraid of process color. Every step in the process must be correct, otherwise the final result will be incorrect. There is at least a dozen things which can be done wrong and effect the final result. This dozen things gets multiplied further by 5 or 6 for the number of screens which need to be correct.
I'm currently working my way though the adobe illustrator sample director. Following that i'll move onto photoshop and corel.
you need to try printing a halftone underbase for your process. Will take it to the next level.
Major areas that need attention
As mentioned above, burning of screens and retaining the halftones
Proper angles for your plates.
Good screens
Good sharp squeegees
Good tight registration press
you need to try printing a halftone underbase for your process. Will take it to the next level.
In order to produce a good halftone, it needs to have a good white. I've worked some with using a black shirt to produce a black background color. In one case it worked especially well. In another case it wasn't so good. From these early tests, it looks like i would need to use both an underbase white along with either a highlight white and/or a halftone underbase white.
Right now i'm concentrating on reproducing the artwork as faithful as possible to the way the original artwork was was created. For any computer generated artwork, the background is assumed to be a true white and it is the color which brings it back to a black. Creatively, there are reasons to change this and use a halftone, but it is nothing essential. Similar to making a halftone of the white, creating a super black can also have it's creative purpose. For example, in the rough mouse, the nose, black lines of the cigar, the tops of the eyes were all converted into a super black.
So it sounds like you really need a 6 color press. CMYK + white underbase. I have a 4 color press so I'd have to do it without the underbase. I have a large UV exposure unit, but it is not a vacuum unit.
I've made screens in the past by printing to a file in Corel, then printing the file to the printer using Ghostscript, which works great. My C8800 has a postscript driver installed, but I can't get it to print halftones directly from corel. It will print halftones from Ghostscript like my other printer though.
So it sounds like you really need a 6 color press. CMYK + white underbase. I have a 4 color press so I'd have to do it without the underbase.
With only 4 colors, you would only be able to print process on white shirts.
Quote:
Originally Posted by rrc62
So it sounds like you really need a 6 color press. CMYK + white underbase. I have a 4 color press so I'd have to do it without the underbase.
Quote:
Originally Posted by rrc62
I've made screens in the past by printing to a file in Corel, then printing the file to the printer using Ghostscript, which works great. My C8800 has a postscript driver installed, but I can't get it to print halftones directly from corel. It will print halftones from Ghostscript like my other printer though.
If the C8800 is postscript, it should have a driver option to print halftones. For my color phaser, i need to tell it to print as b&w fax friendly.
Photoshop can make bitmaps the same as ghostscript and can print to a none postscript printer.
Thinking about this some more, I realize that I don't want to print to shirts, I want to print to transfers, then press those to shirts as they are needed. Would I still need to use a white base seeing as how the transfer is white? Would I lay down colors in reverse? If the proper order is CMYK, would I print KYMC on the transfer. I'd imaging ordering is important so that layer appear correctly when pressed. So if I did use a white under base, in order for that to be an under base on the pressed shirt, it would have to be the top layer on the transfer.
Printing to a transfer might actually let you get around having a 4 unit press. If you custom make a platen which includes pin registration, it might be possible to print process color images, then come back and re-register the transfer to add the white underbase.
Personally, i believe Adobe Photoshop is essential to the production process. If you don't have it, buy it. If you can't afford it, buy an academic copy.
That simply doesn't make any sense. If you qualify for an academic copy you should buy it whether you can afford the full version or not (why not save the money?), and if you don't qualify for an academic copy, you shouldn't buy it, as you wouldn't have a legal copy of the software. Paying money to break the law is just twice stupid.
Ive been using PS for years. I find the half tone filter in PS is more of an artistic effect though. It has never produced a good enough halftone to use as a screen film. Basically, I use PS to work the image, then import it to X3 and print the halftone separations.
Printing to a transfer might actually let you get around having a 4 unit press. If you custom make a platen which includes pin registration, it might be possible to print process color images, then come back and re-register the transfer to add the white underbase.
fred
Would I still need the white underbase? How would an average photo look after pressing with no white underbase? My guess is that the white makes the colors pop. Kind of the same principle as heat transfer on dark, but on the other hand, plastisol is opaque. For instance, I've printed red ink on black shirts with no problems, but that was a straight spot color, no halftones.
You don't use a photoshop filter to make the halftones. You turn on each channel by itself, change the mode to grayscale, then to bitmap, then in the following dialog boxes you put in your halftone dot shape, angle and linescreen. Save the file, then go to the history palette, select convert to bitmap at the bottom, trash it, and click okay when it asks if you want to delete "convert to bitmap". You'll have your original file back with all the channels. Do this for each channel, saving each as a separate file. I save 'em at 800 dpi to gain as much edge sharpness in the dot as possible, and the files aren't that big since they're 1-bit files. You'll get a good usable halftone doing this. The 800 dpi might be overkill, and many say 300 is fine, but if you've ever looked at the difference between edge definintion from a 300 dpi laser printer and a 600 dpi laser printer, you'll know what I'm talking about. I've compared films output this way to ones off of FastRIP and an Epson 2200 and they're as sharp. I'm currently using an HP 9800.
Process screen printing - Photos 
