Indexed color separations, what about the gray?

[danieldanger]

not having trapping for index separations requires PERFECT REGISTRATION, which doesnt really exist. two layers of screenprinted dots are almost never going to sit perfectly against each other without gaps somewhere in the print. how it looks in photoshop is not how it will look printed. i stack everything.

[NeroInferno]

it's for textile.

And if it was for paper?

[B-DROID]

2 words: Dot Gain.
Your dot on press is going to gain anywhere from 20-35% depending on how you print and that should be more than enough to compensate for any trapping needed or butt registration.

[Andymac]

generally, the dots blur out a bit on a shirt, so they can hide any white gaps - plus the print area is small enough, on a good press you can get it to register. It's as good as 4/colour seps, they need to be printed in reg too or they look soft/blurred/weak.

on paper, if you have enough colours, you can take the lightest (or darkest, depending on the print order - essentially, whatever color is being printed first) - and expand the dot/fill it in a bit. this gives you some trap/overlap.

ON a few prints where we had 3 or 4 yellows for example,( or reds, or blues etc) we also just took all the films, sandwiched them, burned a composite screen, and printed a light tint over all the yellows - this pulled them all together and eliminated any white from misregister or drying in.

You will not get good results without experimentation, tweaking, and further manipulation of the files, but I still personally like the colour saturation and softer non mechanical look of index combined with stochastic, when compared to chunky halftones or washed out 4/colour.

[NeroInferno]

Hello guys,
thank you all.

Andy: the point is I cannot expand the dots in Photoshop..the dots are so near between them that also 1 pixel expanded make them a common spot fill. I was thinking to play with the dot gain option into the printing dialog. I'm quite sure I've seen this option under Photoshop but I'm not sure to have seen it on Illustrator.

Thanks for the sandwiched film tip!
Fabio

[aquariusmediaaseo]

Its a very useful post for photoshop users.I like the suggestions and views of the members. Thanks for sharing it with me.

vaastu consultant | Vastu Shastra | Advertising agencies in delhi | vastu | http://www.awebsitedevelopment.com/forum/]webmaster forum[/url]

[ghostfire58]

Try bitmapping the grey with a halftone so you don't lose the details for that color.
I haven't been able to figure out trapping for indexed colors. It seems like it would be a subjective formula that I don't have the patience for.

edit: deleted my mesh recommendation because I didn't realize this was for textile printing

[NeroInferno]

Thanks for the reply ghostfire58

Fabio

[GoldenTers]

Index What is color separation?
It is a process of choosing a few colors to represent millions of colors which developed an image / design. It breaks a million colors in some colors that best represent an image when printed on a shirt back together. Choosing the best set of colors is extremely crucial to produce an excellent impression. The allowed colors is the best image. 12 Index of the color image is softer than a dual-color image of 6 index. Separation of color index becomes a design / image into a dither pattern distribution of random pixels almost entirely kept him out of trouble moiré pattern (waveform cause interference pattern between the angle of the halftone dot and the mesh of the screen).


Why Use Color separation index?
Index Color dot pattern: Diffusion Dither
CMYK dot pattern: halftone

Halftone dots form an image by varying the size of the dots. Different sizes produce different shades, many different hues form an image / design.
Dissemination of random plot points are all the same size, forming an image by varying the distance between the points. Different distances produce different shades, many different hues form an image / design.
Below are the comparison between the index and traditional CMYK color halftone color index to see what stands out as the best solution for the T-shirt printers.

1. moiré
Angle> Different Cyan 15 °, 75 ° Yellow, Magenta 45 º, 75 º Black screen easily take on the problem of moiré.
> The random dot pattern automatically indexed-color silkscreen prevent trapped in moiré problems.

2. color change
> In the CMYK printing process, CMYK inks overlap each other to reproduce millions of colors. No amount of tightening control or uneven bar pressure of floods, the opacity of the ink or the viscosity, poor color separation work, the tension loose screen, easily causes the color change.
> The color index print, each pixel is printed right next to the other. Pixels are aligning with 4 edges touch each other, not overlapping, space. If overlap occurs, this means that logging is disabled. Therefore, any case, such as color change.

3. saturate
> Always printed dot blot 30% to 50% greater than the points in the film. This circumstance called "dot gain". CMYK inks are transparent, more prestige means more overlap so on saturating the printed image.
> In printing color index. Despite the dot gain occurs, there is no room / space between pixels to minimize the loss of prestige also use inks are opaque. Therefore, saturation never occur.

4. Color fade out
> CMYK printed image tend to fade quickly after washing a few.
Home> Color printing will not fade.
[Usually crack. The cracks are due to incomplete fusion (heating process transforms liquid plastisol elastic solid plastic). Plastisol cast at 320 ° F or 160 ° C, duration of 1.5 minutes.]



Indexed Color Dark Side
There is always a "minimum color requirements" for each design that looks good when printed in color index mode. The biggest problem for a good color index print is the lack of printhead, not enough color. 8-color printing (white base and black included) of the machine will be good enough, 10 colors will be excellent! 14 colors will be awarded. I'd say 6-color printing is the minimum (of course, depends on the design).



When the use of use / non-indexed color?
Color index works

EXCELLENT: painting, art, wood / texture of the tree, small but clear wording in the design, detail illustrated surf wear t-shirt art, wildlife art skin detail ... almost everything, but ...

POOR about: gentle slope, shadows, transparency effects, critical, realistic photo images. (No Color Index means that does not work, only that they need more colors for a good performance compared to using the traditional pattern of halftone dots).

What if you go to the index shows a detail gorilla smoking a small but clear wording attached to the cigarette and an evident shadow disappear behind?
> Gorilla skin needs a color index
> Clara writing children need a color index
Shadow> discoloration need halftone.
.....................submit infographics............................