How can Hobbicolors supply only one set of dye inks for all Canons?

[ghwellsjr]

Have you ever thought that maybe everyone else is color blind and you are uniquely gifted. Don't laugh too loud because you see it has happened before. If you are contrary to what the general consensus says then you are wrong. But when you think of it, how does the general consensus determine that they are correct? They can't.

If you recall, back in post #10, I stated that my two eyes have different sensitivities to red. If it were the case that the consensus is wrong and I am right, then I would have this problem of determining which of my two eyes was more gifted than the other.

Your question would apply if there were a uniquely gifted person that could see a wider spectrum of colors into the infra red and ultra violet. It is quite obvious if someone can see more than another person can, just like it is obvious if one person can hear higher or lower pitches than another one. Superman had a unique gift with his X-ray vision eyes.

Color blindness is not like I see different colors than normal people, my eyes are simply less sensitive to certain colors than other people's eyes.

 

[websnail]

Ok... I think I need to lie down... All this philosophical muttering has got my brain to the point of overload...

... oh and in case you were wondering my eyes will be closed so I won't have to worry about whether I can really see what I think I see... or do I??

This could be a loooong night!

 

[Grandad35]

That's why most profile targets contain so many colors - for example here are the 918 colors used by my spectro.

What do you mean by "spectro"? What do you do with it? When I look at something like that (and also the one posted by mikling), I just see a random assortment of colors with no rhyme or reason. I wonder, why are the colors in that particular pattern as opposed to an orderer gradation? I like the color bars I created here because I know what the colors are even if I cannot distinguish them:

I really hate to deviate from this philosophical discussion, but I missed your questions until now.

Spectro is just short for spectrophotometer - a device that simultaneously measures light at many wavelengths to allow an accurate (and traceable back to an international standard) measurement of colors. Before each use, it is standardized against a highly reflective target to correct for any drift in the light source and sensor.

One use is to print a target with a wide range of colors (shown previously) with all color management turned off, then to measure the actual color produced for each patch to generate a table of "If I tell it to print this color, I actually get that color". This table is then inverted to get a table of "If I want to actually get that color, tell the printer to print this color - this is a big part of the "printer profile".

I'm not an expert on setting up these charts, but the random nature would seem to better compensate for random changes in the printer's output over the entire set of targets. Remember that this chart isn't something that is supposed to make sense to our aesthetic sensibilities - the spectrophotometer directly sends its information to the computer program which crunches the numbers and generates the profile.

 

[Tin Ho]

Grandad, I don't consider myself anywhere near being an expert of custom profiling. But I can see a problem profiling this way. What if a color you want the printer to print is beyond the printer's capability to print it. There would be no way that you can tell the printer to just print that color so it would print this color correctly for me. It is a color the printer can not print.

Depending on the gamut of the ink of the printer there are always too many colors that are not printable by a printer or any printer. One easy example. Except Canon i9900 and Pr9000 printers all cheaper printers will print red color in orange red. I believe no matter how you profile them the red is never going to be printed very red. Profiling in this case will not make them to print red. This is why a red ink tank makes Pro9000 a better printer that will print better red. Well, I still heard that it is really pretty orange.

 

[turbguy]

How do you generate the color target to use unless a printer can print it?

 

[Grandad35]

Grandad, I don't consider myself anywhere near being an expert of custom profiling. But I can see a problem profiling this way. What if a color you want the printer to print is beyond the printer's capability to print it. There would be no way that you can tell the printer to just print that color so it would print this color correctly for me. It is a color the printer can not print.

Depending on the gamut of the ink of the printer there are always too many colors that are not printable by a printer or any printer. One easy example. Except Canon i9900 and Pr9000 printers all cheaper printers will print red color in orange red. I believe no matter how you profile them the red is never going to be printed very red. Profiling in this case will not make them to print red. This is why a red ink tank makes Pro9000 a better printer that will print better red. Well, I still heard that it is really pretty orange.

Ah, Yes - the complexities of color management. The printer is sent the full range of color values, including many that are outside of its capability to print. The profiling software looks at the range of colors that were actually printed and determines the color gamut for the printer/paper/ink used to print the targets, then embeds this information into the profile along with the look-up-tables.

You are exactly correct with your implied question "What happens when a color is outside of a printer's capability to print?" This takes us into the subject of "Rendering intents". Any color aware printing program will allow you to select the rendering intent that you want to use for the image being printed. As stated in the link, "Perceptual" is used by most people for photographs. Each profile contains 3 separate tables for 3 of the 4 rendering intents (2 use the same table).

Color management isn't an easy subject to wrap your arms around, but it pays dividends once you understand it. This book isn't for the casual reader, but it will explain the subject in detail (plan on reading it at least 5 times to really understand it). Color management isn't just an abstract idea, all commercial printers use color management - if they didn't, they would lose all of their customers.

Profiles are also useful when having your photos printed at a commercial printer. This link lists the profiles that are available for download in Mass alone! Other states are located on the left. These profiles are used with a program like Photoshop to "soft proof" your images before they are printed to make sure that you will be pleased with the results.

How do you generate the color target to use unless a printer can print it?

You print the target on the printer/paper/ink that you want to profile.

 

[Tin Ho]

Thanks, Grandad. I understand the concept of rendering intent of ICC profiles. Custom profiling is not a medicine that can cure everything. It can not make a set of ink perform beyond its capabilities.

 

[martin0reg]

I am using a IP4000 with non OEM carts and inks (inktech, KMP, bottles from german suppliers, etc...)
I assume that recently most of these inks are adjusted to CLI more than to BCI.

I don't use custom profiles - what would be the right setting in the canon driver to balance the magenta?
For example: minus M+C (what ratio) or plus Y?
If the cange of magenta from BCI to CLI is predictable and measured, an accurate correction in the printer driver/menu should also be possible!?

 

[Grandad35]

I don't use custom profiles - what would be the right setting in the canon driver to balance the magenta?
For example: minus M+C (what ratio) or plus Y?
If the cange of magenta from BCI to CLI is predictable and measured, an accurate correction in the printer driver/menu should also be possible!?

It would be nice if everything was printed using only cyan, magenta, yellow OR black with no need to use more than one ink at any one place on the print, and if the non-OEM inks produced colors that are linear with the OEM ink colors at all laydown rates so that the color sliders in the printer driver covered all situations. Unfortunately, the real world is more complicated than this, and simple linear adjustments can't cover the full range of colors. Profiles can.

Try adjusting the sliders using trial and error to see if you can get acceptable results. If you can, you have solved your problem (but it will take a while and waste ink and paper). Custom profiles work across a wide range of colors, are easy to get and don't cost all that much if you place any value on your time.