Questions about printing designs on fabric 1

[Lyell]

I've been creating tiling patterns in AI, intended for screen display; these were created in RGB 72dpi. Now I'm looking into getting some of these patterns printed on fabric. I've found such a service which can accept .ai files, but their website suggests "Save your files in CMYK color gamut and at 150 dpi or greater for best quality printing". I'm pretty inexperienced, and have some questions about how to do this.

-- So far, I've never really been concerned about dpi, and I have no idea how to convert the file I'm using for testing. Or, indeed, whether converting the file is necessary? Or whether I need to recreate the design in 150 dpi?

-- I have used a bounding box to specify the portion of my design to be tiled. (There are usually parts of my designs outside of the bounding box.) Will this continue to work when the design will be sent to the fabric printer, or do I need to rework the design completely?

-- I have used File > Document Color Mode to switch from RGB to CMYK. This seems to have worked since I could test bringing both the RGB and CMYK files into Photoshop, and see that the RGB has gamut problems, but the CMYK file does not. Is this method OK, or should I be using some other method?

I'd appreciate any advice you can give me. I will raise these same issues with the fabric printing company, but I'd like to feel like not-quite-such an amateur when I correspond with them.

 

[apepp]

...illustrator is a vector program, meaning vector is scalable to any size (in theory) and still maintain crisp...

...illustrator does also have bitmap effects like drop shadows, feathers etc, so the 72dpi you refer to is set in the "effect > document raster effects settings" area of illustrator, changing this setting to a higher value directly affects transparency effects in illustrator meaning they will look different than when they were at 72dpi...

...if your illustrator artwork doesn't have transparent effects, like drop shadows, feathers etc, then this setting of dpi is irrelevant...

...as you are dealing with patterns then i assume you haven't any bitmap effects used so the idea of sending a 150dpi bitmap file will likely not be required (unless your using an online printer who specifically needs bitmap images). They state they accept ai files, which are vector based, so you can just as well send them the vector artwork in ai or even PDF format...

>>> -- I have used a bounding box to specify the portion of my design to be tiled. (There are usually parts of my designs outside of the bounding box.) Will this continue to work when the design will be sent to the fabric printer, or do I need to rework the design completely? <<<

...so long as the design can be tiled, i can't see an issue here, i imagine you have tested your patterns by dragging them to the swatches palette and filling a rectangle, so all would be fine in that case, all they need is the pattern. Patterns nearly always have parts extending the bounding box (no fill, no stroke, sent to back), this would be the norm, it's the "invisible" bounding box that tells illustrator where to crop the patterns, when used as a pattern...

...file > document color mode will indeed change RGB to CMYK, the conversion is dependent of what profiles are used in edit > color settings, be aware that RGB black will render into all four CMYK inks, and RGB white may not always be completely white in CMYK...

...the major fabric printers have color libraries you can download, these colors are composed of swatches that fall within the printers color gamut. It might be worth asking if your provider does and if not then you will have to perform a best guess in CMYK on screen (preferably a calibrated monitor). Obviously fabric printing is nothing like printing on paper, so saturated colors and bright colors won't really be that on fabric, unless your using special inks and not just CMYK...

andrew

 

[Lyell]

Thanks, Andrew -- that's just what I needed to know.

Re the color printing -- I'd found a couple of other sites that print fabrics, but both had a very limited gamut of colors and didn't accept .AI files, so I gave up my idea. But now I've found a service which says it can support the entire CMYK color space. They use reactive dyes, which may make the difference. (Or, of course, they may be talking through their website hat.)

Thanks again,
Lyell