Bleeding blacks

[Grandad35]

I am experimenting with yet another ink supplier, and I am getting a better color balance in the grays than others are reporting for Kirkland Glossy Photo Paper on a Canon i9900. Unfortunately, I am having a problem with bleeding of heavy blacks, as has been reported by others with various inks. I am posting this just to show an example of what this problem looks like in case some may not have seen it.

Both images were scanned side-by-side to eliminate scanner effects. The test pattern on the left shows severe bleeding in all of the areas with heavy black, and the test pattern on the right shows what it looks like when the bleeding was eliminated by changing only the black ink (in this case to some 2 year old photo black formulated for a HP 58 cart). The black used on the left is much thinner (lower viscosity) than the black used on the right. Until I get a better fix, I will just use the old HP black since I have a quart of it.

Just for general information, lowering the black color intensity by 10% reduces the bleeding and actually makes the blacks darker (but still not as dark as the HP black). Lowering the black intensity by 20% almost completely eliminates the bleeding, but now the black areas are noticeable lighter than they were at -10%.

 

[Nifty]

Okay... I'm confused. How could reducing 10% make it darker but reducing 20% make it lighter? That's some crazy ink. Any theories on what's going on / causing this?

 

[Grandad35]

Nifty-Stuff - Note that the blacks get darker as more black is put down (going from left to right), up to the point where they "cross the line" and bleed into each other, producing a lighter gray.

By reducing the black by 10%, the inks are still "over the line" into bleeding territory, but not as far over the line as before, so the muddy grays at the far right are actually darker than before, as is the solid black bar (the 3rd bar up from the bottom - the bottom two bars are so similar that they sometimes appear to be a single wide bar).

Reducing the black by 20% is sufficient to stop the bleeding, but now the reduction in black is so great that the blacks are lighter from the reduced ink coverage.

 

[Scrubking]

Can you explain how lighter colors = bleeding?

Bleeding usually means an excess that usually goes where its not supposed to, but if the color is saturated how can it be lighter?

 

[Grandad35]

Scrubking,

I thought that I saw bleeding at the transitions between the heavy blacks and the other colors, so I just concentrated on the strange behavior of the black as indicative of bleeding. I just rescanned the images at 600 dpi to check, and you are correct - they black does not bleed into the other colors - this is a different problem than bleeding.

There are two additional things that I didn't mention in the original post:
1. When the same printer settings were used to print on regular bond paper instead of glossy Photo Paper, the problem was eliminated. This shows that the proper inks are being laid down, but that there is some strange interaction when the inks hit the paper.
2. The gray areas are still tacky when the paper comes out of the printer, while the same areas printed with the HP black ink are dry to the touch (except for the last black area to be printed just before the paper was ejected, and it is dry within 10 seconds).