Why CMYK 100% density values are different?

[drummerpaco]

Does anybody can explain why the 100% of CMYK density value is different?
I know that opacity % changes through CMYK also as White.

My biggest concern is why 100% Black and 100% White opacity % (or density) is different?
Is this because of Pigment, viscosity or chemical that make the ink?

I am measuring density in White and Black in Transparency and it just came to my thoughts why would be different. I know that physically you will see less light thought the black on film compares with White on Film but I think there should be some sort of knowledge that I am missing about the density value.

One more thing that is any body know what "White Hold Back" is? I am assuming that white hold back is relating with "White opacity" but never heard of the terminology.

[Lukas Engqvist]

Please it is hard to understand what you are asking. Can you explain what process you are printing? What are you printing on? If you print on paper normally the white is the paper. I do not understand what you mean by "100% Black and 100% white opacity %"

Normally only a very small % of printing ink is pigment, but as I say what method of printing, what kind of inks and what substrate would be useful information.

[drummerpaco]

Well we are printing on the clear film. I am in Rotogravure world.
Because you have to print the white ink on clear film, I need to measure the white opacity %.
Then I noticed that Black color has higher density value.
I am printing on to PET12 + Solvent INK

I think I am explaining myself OK

[Lukas Engqvist]

Yes now it is more clear... I am sure you will get some good answer, even if rotogravure is not my area

[Lukas Engqvist]

Seems you are not getting any response…*maybe those dealing with this are hanging out in the Ink Substrates discussion?

[drummerpaco]

I think I should try there.
Since I was studying density, because it is measure of light, I think density should changes depends on what ink the light transmit. man!!! too scientific measurement!!!
thanks

[Bloodsaler]

Do you print in gravure?As I know,gravure ink not consistent like lithography ink,so the color data may be inconsistent too.
Only I guess,as a reference~