RGB to CMYK color loss HELP!

Forgive me if this is an old topic.

I am on the verge of shooting 2000 flowers for a gardening book. As this will go to color separation, the files need to be converted from RGB to CMYK. During the conversion process in PhotoShop a lot of the vibrance goes out of the image. Try it and see for yourself.

Anyone have any tips on getting around this?

sorry for the double post.

No one got any ideas about the RGB to CMYK conversion? Today a printer explained to me that the reason that digital is not as good as transparencies for high quality print media is due to the loss of colour and vibrance in the conversion to CMYK.

I tried converting some of my images and sure enough, it degrades the quality of the image.

I feel that there must be a technique to restore some of the lost vibrance. Does anyone know?

Thanks

The color "gamut" or range of color, is much smaller with CMYK than with RGB.

However, a very effective way to determine if your RGB image has been correctly edited for print is that there should be very little if any change when you switch to CMYK.

Hey St Marks, thanks for your comments.

I wonder where I could find out about editing for print? I need to learn this, so that I can confidently switch to digital in a world dominated by fujichrome velvia.

The cost savings are enormous. I estimate costs of film, processing and labelling and filing to illustrate a book containing 2000 camellias at $AUD20,000 as opposed to around $AUD200 for blank CDs (plus my time in editing and file naming).

It means speculative photography for such a project involves only the "soft" cost of labour, rather than the investment in film and processing.

St Marks said:

The color "gamut" or range of color, is much smaller with CMYK than
with RGB.

However, a very effective way to determine if your RGB image has
been correctly edited for print is that there should be very little
if any change when you switch to CMYK.

Click to expand...

St Marks has got it right. These are two completely color models and the color gamut for CMYK is much smaller than RGB, therefore you may see a noticable change in the colors when you switch.

You can however play around with either your Levels or Curves to compensate somewhat.

St Marks said:

The color "gamut" or range of color, is much smaller with CMYK than
with RGB.

However, a very effective way to determine if your RGB image has
been correctly edited for print is that there should be very little
if any change when you switch to CMYK.

Click to expand...

Thanks arem, I appreciate the comments

I have tried playing with levels and curves to some good effect. I guess I am hoping there are some tried and true tricks to be learned on this technique
James

.arem said:

You can however play around with either your Levels or Curves to
compensate somewhat.

St Marks said:

The color "gamut" or range of color, is much smaller with CMYK than
with RGB.

However, a very effective way to determine if your RGB image has
been correctly edited for print is that there should be very little
if any change when you switch to CMYK.

Click to expand...

Click to expand...

Found some great info over at
http://www.robgalbraith.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=8&t=000672
and
http://www.robgalbraith.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=8&t=000276

james said:

.arem said:

You can however play around with either your Levels or Curves to
compensate somewhat.

St Marks said:

The color "gamut" or range of color, is much smaller with CMYK than
with RGB.

However, a very effective way to determine if your RGB image has
been correctly edited for print is that there should be very little
if any change when you switch to CMYK.

Click to expand...

Click to expand...

Click to expand...

James,

I am finding there is a lot to learn about this subject. Have a look at Ian Lyons' site: http://www.computer-darkroom.co.uk/ which has several very useful tutorials about printing and Photoshop techniques.

I hope it helps,

Nigel.

james said:

james said:

.arem said:

You can however play around with either your Levels or Curves to
compensate somewhat.

St Marks said:

The color "gamut" or range of color, is much smaller with CMYK than
with RGB.

However, a very effective way to determine if your RGB image has
been correctly edited for print is that there should be very little
if any change when you switch to CMYK.

Click to expand...

Click to expand...

Click to expand...

Click to expand...

Thanks Nigel, I am looking at that now

James,

james said:

The cost savings are enormous. I estimate costs of film, processing
and labelling and filing to illustrate a book containing 2000
camellias at $AUD20,000 as opposed to around $AUD200 for blank CDs
(plus my time in editing and file naming).

Click to expand...

Which should take you at least 10mins to 1/2 hour for each image if you're going to colour correct, sharpen, dust remove and otherwise correct the images.

Member said:

It means speculative photography for such a project involves only
the "soft" cost of labour, rather than the investment in film and
processing.

Click to expand...

True, but it depends on the value you put on your time. If you spent 1/2 hour per decent image, for 2000 images you're costing your time at less than $20 per hour. Not very much! Makes the film option look a lot more attractive, doesn't it?

Don't get me wrong, I'm not knocking digital - it just irks me when people include all the savings they make in their comparisons, and fail to include the additional costs (new kit putchase, additional labour etc.).

Andrew

Hello,

you wrote:

"Today a printer explained to me that the reason that digital is not as good as transparencies for high quality print media is due to the loss of colour and vibrance in the conversion to CMYK.

This is partly wrong. A slide has to be scanned, right? A scan from a slide IS a digital image. This image is converted to cmyk. So there is not such a big difference between a slide scan and a d30 image.

You could work like this:

shoot raw, with a custom white balance.
convert the images to 16 bit tiff.
open tiff image in photoshop and adjust Levels and midtones.
convert image to 8 bit tiff.
resize the image for your need
convert it to cmyk (be shure to use the right profile for your needs)
sharpen it with 140 / 1 / 4 in photoshop.
you might afterwards adjust the color intensity.

Greetings

Christian

Member said:

Which should take you at least 10mins to 1/2 hour for each image if
you're going to colour correct, sharpen, dust remove and otherwise
correct the images.

Click to expand...

I estimate about 5-10 mins per image - 1-2 month's work, which will be done if and when I have a publisher's advance. Besides, the files will sit 'raw' on cd until a publisher is found. I can assure you the film would take a lot longer to choose, label, sort and file than this. My company has employed two people full time for nearly two years to manage the acquisition of a library of 14,000 species. This does not include my time making the the pic selections.

Member said:

Member said:

It means speculative photography for such a project involves only
the "soft" cost of labour, rather than the investment in film and
processing.

Click to expand...

True, but it depends on the value you put on your time. If you
spent 1/2 hour per decent image, for 2000 images you're costing
your time at less than $20 per hour. Not very much! Makes the film
option look a lot more attractive, doesn't it?

Don't get me wrong, I'm not knocking digital - it just irks me when
people include all the savings they make in their comparisons, and
fail to include the additional costs (new kit putchase, additional
labour etc.).

Click to expand...

Having looked at 100,000 pics on a light box in the last year, I much prefer the digital option. Have you ever selected, labelled, sorted alphabetically, then slotted into sleeves and filed large numbers of trannies? On top of this are the costs of film, processing, sleeves, rods, labels. The impending speculative photo shoot (that is, shoot now, find a publisher later) would not be possible with film, I just don't have the bucks. But given that I have the equipment and vacation, the labour remains a "soft" cost as I said.

James