It print in RGB or CMYK, The unike thing that I know that it print with lasers (look like RGB??) And if RGB is additive colors, how it can produce black???????
Very likely: sRGB is fine. Ask the lab. If they use a different profile, they can tell you. For critical work, try a test image or 2. Don’t worry about black, the printer does that.
My question, in others words is: In prepress, we use CMYK, because in theory, cian, magenta and yelllow would form black. But they form a muddy brown, whick needs a black ink to form a pure black. (subtractive colors) To monitor, we use RGB, additive coloros, which when the three colors light Red Green and Blue overlap, they form white, ok???
I have thought mini lab prints in subtractive colors too, but today I know it print in RGB. How it is possible, if RGB is additive colors????
The papel which they use is white ( a few rose)… So, I don´t understand. If the lasers is mini lab is red, green and blue, when they burn paper, how could it form black, or pure black???? RGB could be subtrative too?????
Gustavo, I do not know how the printer translates the RGB information to print the correct colors because I am not a programmer. Maybe this link <http://www.computer-darkroom.com/ps7_colour/ps7_1.htm> will help. Pay attention to the discussion under Colour Management Primer Some printers print CMYK specifically, but most printers these days use RGB input to create the prints. Black is still black whether it is on a screen (additive) or on paper (subtractive). -Mike
Photographic paper uses CMY (no K – someone correct me if I’m wrong).
Other print processes put colour onto the page. Photos however have layers of emulsion (one for each colour) which only have colour after being sensitised by light and then processed through chemicals.
Having said that, I have had no colour reproduction problems with photos from RGB. If colour is critical to you, check with the lab and do a test print.
I own a photo lab in El Paso, Texas and we print using a digital minilab, so I think I can answer your questions. First of all, we use real photographic paper – it gets exposed and then run through chemicals. Real silver halide paper offers a stability and longetivity that cannot be matched by inkjet, dye-sub, or anything else out there.
Anyway – silver halide paper uses the subtractive color process. The less yellow light you apply, the bluer the photo is. The paper is actually a negative (remember film?), so throwing red light onto the paper will result in a cyan image. Throwing green light makes magenta, and throwing blue light results in a yellow photograph.
If you want a white image, you allow no light to hit the paper. If you want light yellow, you throw just a little blue light. For dark yellow, you expose the paper to a brighter blue light.
If you want a blue image, you have to expose the paper to red AND green light. (red and green makes yellow, the opposite of yellow is blue)
So how do we get pure black? Imagine a darkroom – if you turn on the lights with the paper out, (then develop that paper) the finished image will be pure black. So in a digital minilab, you need to apply 100% red, plus 100% green, plus 100% blue – in other words, white light – to convert the silver halide to a latent image that will be black once it has gone through the chemicals.
The dyes used in Photographic emulsions are much better at absorbing wavelengths than are the inks used in process printing. Consequently, when all 3 layers of the photographic emulsion have sufficient exposure, the C,M and Y dyes DO produce a dense black, unlike the muddy brown that printing inks produce.
Finally, I have understood the mini lab process. For the last question, I want to know if the RGB´s mini lab color gamut (if is how a negative), it is more or less the same of RGB or CMYK???? (By what I have understood, at true, the lights RGB form, because the paper, a CMY… But and his gamut??? The mini lab knows to reproduce RGB or CMY color space???