Tips and Tricks

yellow and magenta dominant on black and white pictures

Hi,

 I just received my first book which is made exclkusively of black and white pictures.

On most of the pictures, there is a dominant yellow or magenta color. I am not satisfied at all.

I processed my images in greyscale and then converted them to RGB as suggested for best quality.

Has this happened to anybody? What would you suggest ?

Where is the problem?

 PS: i ordered a new test putting my images in greyscale … let see if quality is better and no dominant appear.

Replytopic_b_normal
Posted by
djolamela
Dec 28, 2009 3:12am PDT
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djolamela
 

This can happen if you converted to Adobe RGB or some other RGB colorspace instead of sRGB. 

It is difficult to offer suggestions or diagnose your problems when I have no clue about which software you use or the process/program you use to convert to RGB

Mike

Posted by
Charybdis
Dec 29, 2009 3:25pm PDT
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Charybdis
 

First question is – are you using BookSmart or the PDF workflow? In BookSmart you Must upload RGBs (or grayscales). The grayscales will look weak and flat, as they are just a black only halftone with no under color support.

However, if you are using your own software, as in InDesign, your PDF can go to Blurb as CMYK files. Now you can convert your images to CMYK where you can tinker with the black especially, but also control all four colors. As a rule of thumb, once in CMYK never go back to RGB. You’ll lose too much data.

Posted by
wiliamhoard
Dec 30, 2009 1:21pm PDT
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wiliamhoard
 

Greyscale (or Grayscale if you are from the US)  is not supported by BookSmart, it has to be RGB preferably sRGB. See the FAQ.

…..Tony

Posted by
tfrankland
Dec 30, 2009 1:28pm PDT
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tfrankland
 

Hi,

I am using booksmart and photoshop CS2 to convert my files from grayscale to RGB.

In photoshop "mode", I can only choose RGB. there is no option for sRGB.

How to proceed to get the best black and white quality for my books with no domiant colors at all?

thanks very much

Posted by
djolamela
Jan 3, 2010 7:00am PDT
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djolamela
 

I’m guessing you’re talking about Image->Mode->RGB.  That is not the color space.

I have CS3 installed, but I can’t imagine it is different.

Close your files.

Under Edit->Color Settings, you should see a group box that has "Working Spaces" as a name.  In there is a drop down box that is titled RGB.  In that drop down box is "sRGB IEC61966-2.1", "ProPhoto RGB", "Color Match RGB", "Apple RGB", and "Adobe RGB".  Pick the sRGB option.

In the Color Management group box check the two "Ask When Opening" boxes.  If PS is setup this way, it will tell you the name of the color space the photo was saved in if it wasn’t sRGB and will give you the option to convert it to sRGB on open.

Mike

Posted by
Charybdis
Jan 4, 2010 11:51pm PDT
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Charybdis
 

This was the reason I converted my images to duotone. 

Black & white (greyscale) comes in 256 shades (or "values"), from pure white (O) to blackest-black (255) and all the incremental "grey" values in between. (Think of a gradient from white-to-black.)

Yet in reality, only about 50 of those "values" will actually print nicely, and the tonal shades between many of them will block up and lose tonality and subtlety

That’s the purpose of converting to duotones, tritones and quadtones in the first place.

They bring a little "colour" to intensify and broaden the tonality. Check the very best black & white photo books, Cartier-Bresson, Ansel Adams, Walker Evans, etc., they are usually printed in duotone, not greyscale halftone.

I have done this before ~ designed in InDesign for export to PDF and never had a problem with a variety of printers (I was formerly a magazine publisher, now a fulltime artist).

I expected I could do the same here – but Blurb seems fairly ignorant about the process (check my other thread about duotones) and instead is telling me to go back into PhotoShop and convert those duotones to CMYK – an INCREDIBLY laborious step that may not even be necessary.

Truthfully, it makes me skeptical about quality control at Blurb. I mean, they are a professional publication company, yes? And many photographers work in b&w and want to see the best results in print, agreed?

Why then (our team keeps asking ourselves) doesn’t Blurb post formal instructions on their website about how to best produce high-quality black & white images for publication; and why there is zip-nada-nuttin’ about duotones, tritones and quadtones? They really need to get up to speed for artists to inspire confidence. Right now, I don’t have much…

I’m crossing my fingers that these guys know what they’re doing, but not holding my breath.

My original intent was to place an order for ten books (at $140 per); but the dodgy insecure answers I’m getting from them have me too skeptical and worried, and I’ll instead buy ONE book. If it looks okay, then I’ll order more.

Posted by
tekapo
Jan 9, 2010 11:51am PDT
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tekapo
 

I don’t know about duotones, but most colorspaces use 0 for lower intensity (i.e. rgb =0 0 0 is black, rgb = 255 255 255 is white).

As far as Blurb goes, I believe it is just growing pains.  Initially they only offered jpg format in sRGB, now they have pdf in sRGB and CMYK.  Jpg is universally used in digital cameras, and sRGB is a public domain colorspace.  Maybe in a couple of years they will offer duotones. 

I don’t think they try to put themselves out there as a "professional publisher" in the sense that businesses that want top notch pulications would use them.  Blurb offers one of the lowest cost publishing services to people who want to preserve memories or express their creativity in a book form. 

I’m sure there are many "professional publishers" out there that will be happy to take your duotone format, but it will cost you much more than you’ll pay Blurb.

Mike

Posted by
Charybdis
Jan 9, 2010 3:05pm PDT
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Charybdis