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Random white spots on red.

IsItFasst

New Member
So I notice every so often that for some reason I get a white fish eye when printing red. Doesn't seem to happen on others colors. Or at least not enough that it is a concern. But happens enough when printing red that it does concern me since reprints are often required. It would seem the media may have some contamination if this did it on all colors but really only see it on red. Any reason why or is there a fix?
 

IsItFasst

New Member
File Aug 29, 7 45 30 PM.jpeg File Aug 29, 7 45 43 PM.jpeg The first picture shows the issue. But in picture 2 you can see that even where the red and black meet up it only seems to happen on the red part. It's like if the black ink hits that contominated area (if that is the problem) it has no issue covering it up. FYI. This is Orajet 3164 but I think it has happened on several rolls and brands since it has been happening for months now.
 

IsItFasst

New Member
We try using another color palette and it sometimes changes things enough to resolve many issues.
The problem is I have about 10,000 files using this red as it is the standard red in Flexi so not really an option for me. Luckily it's been rare enough not to be of too much concern but sometimes it comes up so often I have to reprint something 3 times (as was the case yesterday when I posted this). And I am using OEM inks....always have.
 

IsItFasst

New Member
A year later, still having the problem. Just took me 9 prints to get 2 decals that were usable (on Arlon DPF 8000 this time). Luckily the decals weren't huge but still a PITA to constantly having to reprint.
 

eahicks

Magna Cum Laude - School of Hard Knocks
I seem to remember having weird stuff like that happen on our old Roland. I guess switching to all HP Latex solved it. :)
 

equippaint

Active Member
This is no help but Ive had it using oracal 3551 and only on the red. It was fairly bad on 1 roll so we chalked it up to contamination but still get it every now and then. Using oem mimaki ss21 ink.
 

IsItFasst

New Member
Yeah, it's just so odd that it only happens on red because it looks like contamination of the roll but you would think it would do it on other colors if so or just on one particular roll.
 

CSOCSO

I don't hate paint, I just overlay it.
I think you are over saturating the red. Looking at yout tiny pics one sharper image shows dark clouds in the red. You are printing way to much red on that material and it can't handle it. What material are you printing on? Try to use a different profile. Not sure what rip software you use. i had similar issue and i had to custom create a profile. Well. basically i just took an existing profile and lowered the total ink limit to like 200 from 220.
Try to see what is the total ink limit on the profile you were using. try to lover it. 200 should be enough for any print. I won't go lower than 180 total ink limit.
 

Andy D

Active Member
I think you are over saturating the red. Looking at yout tiny pics one sharper image shows dark clouds in the red. You are printing way to much red on that material and it can't handle it. What material are you printing on? Try to use a different profile. Not sure what rip software you use. i had similar issue and i had to custom create a profile. Well. basically i just took an existing profile and lowered the total ink limit to like 200 from 220.
Try to see what is the total ink limit on the profile you were using. try to lover it. 200 should be enough for any print. I won't go lower than 180 total ink limit.

Agreed! This is what happens when your ink limits are too high. Not only are you wasting ink but the ink is pooling away from contaminants before the ink has a chance to dry.
And yes, your ink limits can be too high for some colors and not others.
 

Andy D

Active Member
A work around until you fix your ink limits is to give your ink more time to dry by:
1. raising your curing temps.
2. raise your print passes.
3. print uni-directional.
 

Pitzu

New Member
A work around until you fix your ink limits is to give your ink more time to dry by:
1. raising your curing temps.
2. raise your print passes.
3. print uni-directional.

Those are good ideas except more passes means more ink, and you don't want that since there's too much ink already.
 

Solventinkjet

DIY Printer Fixing Guide
You sure about that? I have never noticed that to be the case....

I think it's a myth in the industry for some reason or another but you are correct that pass count doesn't affect ink saturation. If you are printing 720 x 720 4 pass, it prints 180 dots per pass to eventually add up to 720 so there are always 720 dots printed no matter how many passes. The reason this helps when you are over saturating prints is because it gives each pass enough time to cure before the next layer is printed so it doesn't pool up and have a hard time drying.

This is also why you can't have a 720 x 1080 profile print in 4 pass and the lowest pass count you can print is 6 because each channel has 180 nozzles. So if you divide 1080 by 4 you get 270 which is more nozzles than the head has to fire but if you divide by 6, you get 180. It's also the reason 360 x 360 resolutions can only be 2 pass.
 

IsItFasst

New Member
I'll certainly try these recommendations. But since it only happens with solid red and is so few and far between it may be a while before I can report back with any updates on what works or doesn't. I really don't want to do any dramatic changes since the colors print so great using this profile I tweaked. But limiting ink may help.
 

Pitzu

New Member
I think it's a myth in the industry for some reason or another but you are correct that pass count doesn't affect ink saturation. If you are printing 720 x 720 4 pass, it prints 180 dots per pass to eventually add up to 720 so there are always 720 dots printed no matter how many passes. The reason this helps when you are over saturating prints is because it gives each pass enough time to cure before the next layer is printed so it doesn't pool up and have a hard time drying.

This is also why you can't have a 720 x 1080 profile print in 4 pass and the lowest pass count you can print is 6 because each channel has 180 nozzles. So if you divide 1080 by 4 you get 270 which is more nozzles than the head has to fire but if you divide by 6, you get 180. It's also the reason 360 x 360 resolutions can only be 2 pass.

And that's correct. I won't argue with that. I used to think the same way too. But in reality, when I tried to eliminate the over-saturation by increasing the number of passes, the result was the opposite.
The second thought would be..the color profiles I'm using are not good, even if there are made for that type of media. And that is also true in theory. In reality, it's not that simple. There are many factors involved.
The explanation is that you increase the number of passes when you want to increase the resolution or ink coverage and thus the quality. In case of ink coverage, you have more ink.
What is higher resolution? More dots/inch. More dots/inch means that the distance between the dots...decreased (the dots are closer to each other).
That drop of ink won't stay there, it will spread (unless we are printing with gel). We all know that liquids have the tendency to spread, even at high viscosity and on a perfect leveled surface. If you decrease the distance between two drops of liquid the probability they will combine is higher and create a pool faster. Ink pool you don't want...colors start to mix and that's over-saturation.
See the resin label doming technique.. they put few drops of resin with a distance between them and let them spread till they became a single uniform surface. If you put the drops closer to each other, they will became one faster. What happens afterwards is important too. If the surface is not perfectly leveled, the resin will tend to travel in the direction of the slope, leaving less resin on one side and more on the other side.
That's why we don't have ink uniformity on the prints when having over-saturation, and we see it more pronounced on larger areas. The substrate is never perefectly leveled, due to many factors: humidity, temperature (causing the material to stretch, become wavy, curl), printer not leveled, etc.... and the ink will tend to travel and settle uneven.
We say...that's why we have color profiles, to control the amount of ink. But when we do color profiling, we do it on small squares where the probability of the substrate to be uneven is less and with an amount of ink limited to that little square. In that little square the ink won't spread so quickly because we have less forces to break capilarity and the surface tension. But if the surface of the print is larger, the amount of ink is bigger (per overall), it will create a pool faster and the forces that drive the ink to migrate are..stronger, so the pool travels..faster. Don't imagine that the ink drops cure instantly. It doesn't happen even on UV printers (due to the fact that UV lamp's efficency is not 100% and other factors involved).
Also, printing media can have different properties (absobtion rate, porosity), even from the same lot...sometimes even in the same roll. The actual fabrication technology cannot assure a continuous perfect constant quality. Actually, this is why you see people having different results for the same brand of media, same printer, same ink and same color profile. You'll see even the same person saying that one brand is better and after a while being dissapointed. Of course, this is just one of the multiple causes. The ink is subjected to this inconsistency in manufacturing too. Also temperature variation in eletronics and printheads can have an impact in print quality.

As a conclusion: ink over-saturation is controlled by the color profiles, but the higher the resolution is, the less forgiving to the media, ink quality and color profile will be and more temperature dependent...and the probability of forming an ink pool is higher.

I'm sure this could have been explained much better in less words, but unfortunately my native language is not english.
I'm also opened to critics and counterarguments. I'm sure we'll all benefit from it ;)
 
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IsItFasst

New Member
So I had a print to do with small red lines so thought I'd limit ink by 10% on this print just to see how it looked. All that did was cause my reds to be more "washed out" looking and oddly a small dot still appeared on the red.
 
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