Blending colors in Illustrator

[Jwcontractscreen]

If I need a gradient effect to blend from one color to the next in Illustrator, I cannot just use the gradient tool and put one spot color at one end and the other spot color on the other end. Accurip to 4900 leaves missing dots instead of actually making the dots next to each other.  Corel did this right, but Illustrator is not working the same.


I have attached the portion of the file that blends nice on screen, but not to film.

[Denis Kolar]

make a solid blue shape. Copy and then paste on top. Color the new shape with the Reflex blue gradient that goes from color to white. Put in on Multiply effect or tell it to overprint.
There you go

[Jwcontractscreen]

That helps some, But what If i'm printing wet on wet and I just want to print a straight blend and not print the base color and then a color over, but I want them to touch dot to dot like if you were doing it in simulated process, or how Corel makes the colors blend?

[Denis Kolar]

Then run the blue gradient the opposite way (solid color shape)

[Gilligan]

I asked a similar question a while back.

50% one color at 55 lpi at 22.5 and 50% 2nd color at 55 lpi at 22.5 will lay down dots right on top of each other.

[ZooCity]

Search around here for a thread on this, I posted a small diatribe on it a couple years back and I think I chimed in on a more recent one.  Your concerns on WOW printing are valid, the old "flash a solid layer of one color and put the other color in the gradient on top" does not yield a superior blend.  To this day I'm still looking for a RIP or something that will overcome this issue.

So Corel's gradients output interlocking?  What RIP are you running to?   This is interesting to me as I'm fairly certain the issue stems from adobe's output or build of the gradients, not the RIP. 

[Gilligan]

This is interesting to me as I'm fairly certain the issue stems from adobe's output or build of the gradients, not the RIP.

Why do you think that Chris?

It just tells the RIP 50%, the RIP places the dots based on the information of the percentage.

[ZooCity]

I need to correct what I said earlier, we're talking about "offset" dots.  Truly interlocking dots would mean one of the gradient colors is outputting as a negative, punched out by the other and this is only achievable by doing it manually in PS or the like as far as I know.  Although a 2 color, true interlocking gradient yields a fantastic range of color in my experience I'm unaware of a way to auto output that.

This is interesting to me as I'm fairly certain the issue stems from adobe's output or build of the gradients, not the RIP.

Why do you think that Chris?

It just tells the RIP 50%, the RIP places the dots based on the information of the percentage.

Right, but it also tells the RIP 50% for the other color, at it's 50% point.  Presuming all screens are at the same angle and LPI, dots will output stacked, not offset.   That is unless you use two gradient layers of the same element, one for each color; stack and overprint one of them and then use gradient sliders to adjust each so they are not both printing their 50% value at the same spot.  This equates to less "white space" but is a major pain in the ass with some art that has multiple gradient elements that all need copied/pasted/aligned.  It can also mean that some dots are still going to stack on each other.

You can also offset the dots by setting your angle differently on each color but this requires testing and you have to bear in mind optimal screen angle to mesh count as well to avoid the dreaded moire on press.

My comment on this being an adobe thing relates to the fact that Illustrator, for example, will show you a nice yellow to red, middle blend to orange on screen using the gradient fill.   Then it will go and output each color in a manner that could not possibly create that on screen image using the coarser dots textile screen printers use.  Maybe this would look fine at 300lpi printed onto white text stock as each of the colors dots would overlay and your eye would fill in that white space, creating the illusion since you are not able to see those tiny dots.  Main point is that I don't think there is a single feature in the adobe suite geared toward our specific techniques, could be wrong about that, but it's something to bear in mind.   This software was intended to primarily serve a very different print industry.

[Jwcontractscreen]

When you do a spot to spot blend in Corel and then print the films, then line the films up on top of each other, it looks like a solid black shape, no overlapping and no white spaces. If you put it together after printing form Illustrator, you get overlapped dots and white spaces.   

I'm certain that it's Illustrator. Using the same rip Corel will make it work. I have just switched over to using Illustrator and wanted to keep it that way.

[Sbrem]

Have you considered asking AccuRIP this question?

Steve

[ZooCity]

Have you considered asking AccuRIP this question?

Steve

I've spoke with Charlie about it at pretty good length in the past and he had the same conclusion.

jw, could you post a pic of the corel output?  It sounds like it is truly knocking out the dots of one color to the other which is ideal.