Copying the look of traditional DieSub Screen (halftones) on a digital printer

[Timothy_Foolery®@adobeforums.com]

I'm trying to get the same look as I would printing to film (with halftones) and then screen printing onto papers (big ones) one colour at a time (using a clam shell printer) from a Roland SJ-740 (retro-fitted for DieSub inks). Confused? Me too. :)

I design and manufacture custom sublimated sportswear for the local and international market. We're getting some repeat orders coming through (football season coming up) for jobs that were printed traditionaly (on the clam shell). These re-orders are much smaller than the original runs (just topping up) so it'd be better to fire them out on the digital seeing as the setup costs are much lower. The problem is the digital produces nice clean gradients, but so they look the same as last time - I need them to be dirty great 30 LPI dots!

I know how to create Rider files, etc. that's how I make the film work for setting screens, but I don't know how to over-ride the RIP (Roland Color RIP (a stripped down Wasatch version)) or set it's halftone properties to allow me to do this. I've tried playing with the Halftone properties settings in the RIP, but they don't really make much sense (to me anyway).

Anyone have any ideas?

[Dion_G@adobeforums.com]

Tim, looks like you Stumped the Band©Dave Letterman

[Timothy_Foolery®@adobeforums.com]

You hum a few bars and I'll smash your face in. ;)

-Madness

[B. Philippus]

Timothy:

Taking the risk of sounding like a complete idiot®, but what if you install the generic ppd that comes with Illustrator, and then changing the lpi settings per color...?

Bert

[Timothy_Foolery®@adobeforums.com]

The thing is it has to go through the RIP. I save it as an eps and then send it to the Colour RIP which sends it to the Roland. I guess the Roland mustn't speak PostScript or I could print straight out of Illy using the generic ppd. I think that's how it works anyway. (I may end up being the complete idiot® here)

I was hoping my Rider would stay attached to the eps (I'm sure it is) I just don't know how to make the RIP/Printer take any notice of it.

[John_Kallios@adobeforums.com]

If I understand this correctly…

You want to simulate a dot pattern on a contone device?

Well, I know of some rips that have the feature (not that it will help with your situation or do I even remember the rips that have the feature nor the name of the feature :()

I will keep my eyes open for a solution but don't hold your breath. B)

[Timothy_Foolery®@adobeforums.com]

Thanks John, that's very kind of you.

I'm not going anywhere and neither is my problem. :D

[John_Kallios@adobeforums.com]

Well, you are not going to like this suggestion and you may have already thought of it. It is a bit of a pita.

Print each separation as a separate postscript file.

In Photoshop, open up each image at desired resolution in grayscale and convert to bitmap using halftone with desired lpi, dot shape and angle.

Back in Illustrator, place each bitmap, colorize it to the appropriate swatch color, set it to overprint or multiply and repeat with additional separations. (you must overprint or multiply for this to work)

No need for the rider file to begin with.

You can now image and it will contain your desired screening. Though a real pain. If I think of anything better, well, you know the drill.

This method screams for actions and scripts.

[Timothy_Foolery®@adobeforums.com]

That's actually a pretty good idea mate. It might just get me by for now. I'm off home right now, but I'll give it a go in the morning.

Thanks for that. :)

[Timothy_Foolery®@adobeforums.com]

I had some trouble getting nice halftones when converting to bitmap in Photoshop John, but I used a similar method involving the "Color Halftone" filter instead. As you probably know that filter isn't really that accurate, so I worked out how many LPI it gave me and how many I needed, then scaled my image up, applied the filter and then scaled it back down in Illy. a bit of a drag, but it's going to see me through untill I can find something better.

Thanks again and let me know if you have any other ideas! :)

[John_Kallios@adobeforums.com]

I glad you found a workaround that worked for you. I was thinking of suggesting the "Color Halftone" and scaling but I ruled it out because I thought you wanted a different dot shape.

Anyway, I am glad you got it through. :)

[Timothy_Foolery®@adobeforums.com]

I thought you wanted a different dot shape




I managed to get everything to look pretty close. DieSub is really forgiving because you're turning the ink on the paper into a gas and impregnating it into fabric when you press it

The annoying part is having to press material to colour test. The digital printer isn't really that bad, but the printers in the factory use traditional inks and the difference is staggering. A vegas gold colour looks like a silver grey before it's pressed. Then of course every media (fabric) you use gives you a different colour.

[Timothy_Foolery®@adobeforums.com]

I've stumbled across a little problem. I've got a halftone vignette that I need to use one of the spot colours (on top of CMYK) to reproduce. When I enter the eps containing the raster element into the RIP and allow raster spot colour replacement it seems that there is more than one colour in my vignette. I'll select a colour to replace and make my changes and only a few random dots will change. If I click somewhere else in the vignette I find it has a slightly different CMYK "in Value". Even if I bring it in as 100% C it doesn't seem to stay that way. Does anyone have any ideas?

I just had one while posting this, but none of mine have worked so far today...

[Timothy_Foolery®@adobeforums.com]

I just read my post and it's a little confusing. You'll have to forgive me, I've got the flu.

[John_Kallios@adobeforums.com]

Yep, you lost me.

This is what I am getting…

You have a gradient comprised of cmyk + 1 spot.

When you send the file to the rip, the cmyk build is changing?

I am confused about the spot replacement affecting only a few random dots.

Are you going through that pita workaround to achieve halftone screen output?

I am pretty sure I can help diagnose the problem if I was able to see the file. If you care to send it…

john(at)orionprinting(dot)com

or if it is too large, email me and I reply with my ftp info.

Or if you choose not to send, no hard feelings.

Sorry about the flu.

[Timothy_Foolery®@adobeforums.com]

I'd have no problem sending you the file John, but as it turns out I don't need to. I fixed the problem and I'm on a roll again. I don't want to elaborate as it turned out to be due to my own stupidity. %D

[Timothy_Foolery®@adobeforums.com]

FYI, it wasn't a gradient going from cymk to a spot, but rather one that includes one of the spot colours I use to extend my CMYK gamut. Just to make things even more cofusing I stick a Deep Blue spot cartridge in the Green slot and bypass the device colour management to make it work.

My colour was:

C= 204
m= 178
y= 0
k= 127
o= 0
db= 128

Because the printer thinks the Deep Blue ink is actually green I have to replace the spot colour in the RIP and bypass its colour management. Good fun eh?

[John_Kallios@adobeforums.com]

Lots of fun.

(making the crazy gesture and pointing towards Mr. Foolery to other users while Mr. Foolery is not looking.)

Glad you tamed the beast. :)

[Timothy_Foolery®@adobeforums.com]

I know it does sound crazy, but there's no profile for the deep blue spot colour, so it's just something I have to live with. It just means I have to work off the huge custom swatch charts and not take too much notice of how it looks on screen. %D