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JV3 Color Problem

genxsignshop

New Member
when i try to print black, set the color to 255 black only, i still get all 4+ colors printing...what can i do to correct this? what could be causing this problem?
 

TheSnowman

New Member
I believe someone talked about this before, did you try doing a search? I don't get what the problem is if it's printing black. Black is black. How can you even tell if it's using other colors?
 

Letterbox Mike

New Member
There are ways arount that but we'd need to know which RIP you're running? 4-color process black is the standard way most RIPs interpret black, no matter how you have your file set up. If you're not getting the correct shade of black, it's something to worry about, but if you just want solid black, let it do it's thing, you'll get a nicer richer black than if it just used only the K channel. Grayscale is another issue altogether, without perfect media profiles you will get non-neutral grays meaning there is too much of one or more of CMY in the gray, giving the gray color a cast, usually green.

But if you just want black, stick with process black. I assume you're thinking if you print black with just the K channel you'll cut down on ink use.
 

Rooster

New Member
You're sending the rip RGB info, when you should send it as CMYK.

It may look black on screen, but to achieve a 255/255/255 level of density your rip will automatically add booster colors under the black. Because the conversion from RGB to CMYK automatically creates the black channel info, there's no way to avoid additional colors in what seem like neutral greys and blacks from printing. If you send it CMYK input with 0C/0M/0Y/100K you'll get just the blacks printing like you want. Although you may find the blacks appear a little weak in comparison to the boosted blacks you were printing before.
 

thewood

New Member
What RIP are you using? In Flexi, for example, you can set up your black as a spot color, and it will print using only the black ink. Otherwise, your RIP is most likely going to interpret your RGB black as mix of all four colors.
 

genxsignshop

New Member
ok, i'm running wasatch, don't recall what version right now. i did not send an RGB image. It is CMYK. When the machine was first setup, the tech that I was working with showed me had to do absolute black, we made a profile for it so whenever black comes up, its absolute black with only 255 on the black channel. I've worked in printshops most of my adult life, so i know how to look at the dots and i see all 4 colors coming across...not just black. and when it prints, its not black, its is kind of a dingy brown/black. if you are not putting it on something black, then its fine. for this instance, i was doing numbers on a wing of a sprint car. i had to do a flood black behind the number because the driver wanted to cover a previous number rather than pealing it all off. from the stands, i could see the color difference.
 

Modern Ink Signs

Premium Subscriber
Once you get your problem fixed you will still want to print the black with all 4 colors. Just not as much as what you are probably getting now.

From my JV3 I run VECTOR ART BLACK at 15/15/15/100. It makes the black a very nice and rich looking and not too much ink on the media.
 

Rooster

New Member
Where are you setting the black only channel to 255?

RGB uses increments of 0-255
CMYK uses increments of 0-100

Saying you set a black only channel to 255 has me very confused.
 

myronb

New Member
Where are you setting the black only channel to 255?

RGB uses increments of 0-255
CMYK uses increments of 0-100

Saying you set a black only channel to 255 has me very confused.

Me too! I would like to know exactly what you are doing. Depending on the job & how black we want, we use 20,20,20,100 or 40,40,40,100.

Myron
 

genxsignshop

New Member
in the wasatch rip....the cmyk channels go in increments of 0-255. when you are wanting to color match a PMS color, you go by the cmyk #s on the pantone book and multiply each # by 2.55. so is cyan is 100, you have 255, if magenta is 45 it would be 115, so on and so forth.
 

Rooster

New Member
OK. Now my question is why are you setting the CMYK colors in the rip?

When you sent the file in question was the black sent as 100% K only? Was there an input profile attached to it, if so what was it? What was the output profile?

There's some pretty confusing info in this post. You've stated you want to print 100% black only, but then you say the print looked weak in the blacks. Dropping the booster colors will produce a weak black, but you say they're printing with the black and it still looks weak. You shouldn't be able to really even see the other inks if the black was printing @ 100%. This leads me to believe the black isn't printing @ 100%.

I'm trying to help as much as I can, but until my version of wasatch shows up here (about a week) you'll have to provide more detailed information.
 
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