Blacks and Blacks?

[Graywolf]

Hi Im a lurker coming out. When I first got my i9900 (2months old) I did a few grayscale 13x19 that had a good black with oem ink, after refilling with MIS ink and made reprints for friends, the prints are very warm almost brown using grayscale. My question what other ink suppliers would you recommend for black inks?

Thanks
Graywolf

 

[Grandad35]

Graywolf,

Welcome to the forum.

The problem is that these printers don't just use black ink to print grays and blacks - they blend C/M/Y for the lighter grays and only start to use black ink for the darker grays. Canon supplies built-in "printer profiles" for their inks and papers to get good color with their products. AFAIK, there are no alternate sources of ink that exactly match the Canon ink. This is why some of us use "custom profiles" - they modify the color information transmitted to the printer to get the correct colors.

Read this thread as a starring point (http://www.nifty-stuff.com/forum/viewtopic.php?id=118). There are several profiles in the forum (http://www.nifty-stuff.com/forum/viewforum.php?id=8) for your printer, but none of them are for your ink. You could experiment and see if any of the profiles works with your ink, or you could buy a custom profile from someone like Dry Creek or Cathy's Profiles.

This isn't an easy subject to understand, so don't worry if it doesn't make much sense at first.

 

[Graywolf]

Thanks Grandad35, question if you check the grayscale print box in the printer option window is that not the black ink only, under a 10x loop there is no other color shift, if you leave the grayscale box un-check then the print takes a different hue that has color mix.

thanks for your input

 

[Grandad35]

Graywolf,

Sorry for the delay, but I wanted to run a few tests to check some things.

1. I generated a white ==> black gradient and printed it both in color and grayscale mode, keeping all other settings exactly the same.

2. I used a cotton swab to make some patches of black ==> gray on the same glossy photo paper using the same black ink. To get the lighter colors, the swab was rinsed out and the excess water removed on a paper towel in successive steps to dilute the ink.

3. All 3 images were scanned side-by-side on the same scan at 600 ppi, imported into PhotoShop and converted into aRGB using the scanner's profile.

4. I noticed that the grayscale print was "grainier" than the color version. To check this, the same section of the color and grayscale images were converted from color to grayscale (to eliminate any color casts - that will be covered later) and displayed at 400% - the width of this image is about 6 mm (1/4"). There is clearly more "grain" on the grayscale image.

5. It was my opinion that the color gradient looked to be slightly more linear than the grayscale gradient. The light "levels" were adjusted so that the lightest and darkest areas in both images were the same for this comparison. Here is a slice of each gradient.

6. The original versions of both images were adjusted to get the same light levels at each end as above (this increased the intensity of the color casts without affecting the colors - the casts in the original prints are not as severe as this image indicates) and are shown below. The numbers are the Red/Green/Blue values (0=full off, 255= full on) at several positions across the width. A "pure gray" color will have all 3 values the same; the more these values differ, the more obvious is a color cast. For example, a set of 214/211/213 is very close to gray, while a set of 109/103/79 is missing a lot of blue and will have a yellow cast. The "color" print has an area where there is a blue cast (147/146/162 - a variation of about 10%), but the grayscale sample is light on blue over a much wider area (and as much as 30% lighter). More on this subject later. NOte - these images are in the aRGB color space; if your computer converts them to sRGB you will get different color values (but the same colors).

7. The swab sample was processed in the same way, but it was difficult to get good color readings with so much variation. To get good readings, the patches were copied and a "Gaussian blur" was applied to get an average color. The average values for these patches are shown below. Note how much closer these values are on all but the darkest patches. This could be an ink issue or a problem with the scanner calibration - it is very difficult to color calibrate a scanner on very dark samples.

Summary:
1. The black swatches gave reasonable gray colors - better than the grayscale print.
2. The grayscale print had a noticeable yellow color cast over a wide range of grays. I don't see how the black ink could give this color cast. I suspect that when you select grayscale that the printer uses a built-in profile designed specifically to give good grayscale images with Canon inks, and that this profile doesn't work well with other inks. The color and intensity of the color cast will be different for different inks.
3. The (profiled) color print is closer to gray than the grayscale print, but it still has a blue cast in one area and a light yellow cast just to its right (yellow is exactly the opposite problem - too little blue). This indicates that there is probably a mismatch between the Formulabs cyan and photo cyan in the area where the printer transitions from PC to C, and that the profile can not correct for this rapid transition.
4. In most printer drivers the word "grayscale" just tells the driver to discard all color information, not which inks to use. My HP 5550 has a separate box marked "Black Print Cartridge Only" so that you can specify whether to print a grayscale image with CYMK or only the black ink. From everything that I have read, Canon doesn't give you the option to use only the black ink.
5. Both Epson and HP offer printers designed to produce good B&W prints. These printers include at least 2 additional intermediate gray inks to improve the printing on the lighter grays. They wouldn't go to this much trouble if black worked over the full range of grays, for much the same reason as why they include photo magenta and photo cyan.

If you get prints that don't have a color cast on the grayscale setting, why look for another ink? Did you try a grayscale print when you had the OEM carts in the printer? If so, was it a good grayscale.

I also printed a few B&W photos in both modes as a "sanity check" and found that I actually preferred the grayscale prints with the yellow cast - it gave the a "sepia-like" look that was similar to some old B&W photos that we have.

 

[Graywolf]

Thanks Grandad for the time and work you put into this.

You ask why look for another ink if I like the OEM print, Cost and the KISS principle, refilling makes sense and being able to stay with one ink source keeps things simple. But the Canon OEM black does make a less warm looking print for me. I do have an Epson C86 with MIS black ink set (pigs) just 8 x 12 max print size. The i9900 makes great color prints ), just trying to get 13 x 19 bw prints without the Epson clogs. Thanks again for your time.

Mike Lambert

 

[Grandad35]

It has been bothering me why I like the look of my B&W prints with a yellow cast over "true gray" B&W prints. I scanned a B&W print that was made 25 years ago by my father-in-law in his basement dark room using silver halide paper. It has been hanging in my hallway behind glass in a smoke-free house and out of direct contact with any light (not just sunlight). There is no apparent sign of fading and it has what I consider to be a classic "B&W look". Here are some R/G/B values that I measured after giving it the same scanning/light adjustment procedure as the previous images.
21/26/13
43/45/28
61/64/53
77/79/64
90/94/76
99/102/85
139/139/120
203/201/185
231/226/211
In every reading, the red and green values are very close, but the blue is always lighter. Light blue readings ==> a yellow cast. This would seem to indicate that conventional B&W prints are not really black and white.

I then toyed with the color adjustments in the print driver and found that values of:
Yellow = +50
Cyan = -50
Magenta = -30
Black =-5
gave a much more pleasing (warmer) result, even though it was no longer a "true" B&W. Maybe this is why Epson and HP have special gray inks - to give them a controlled yellow cast. You might want to play around on your printer and see what works best for you with your inks and papers.

I don't print a lot of B&W, but I will definitely try these settings when I do.

 

[Nifty]

Very interesting! Thanks for all your work on this Grandad. I've not done a lot of BW printing, but when I have they seemed to look pretty good to me. A few months ago I printed a BW photo of my grandparents for my mother. My wife was putting that photo up with some other BW photos (printed at a photo store) and the one I printed looked considerably more blue. I think I'll play with my own color adjustments next time I print a BW photo and try a more yellow / magenta cast to see how I like it.