Tips and Tricks - A tip for better looking Grayscale images

Helmet_of_Poe

Active member
Here's a cool trick to get (usually) better looking and printing grayscale images from CMYK or RGB images. This works best on darker images when you're concerned about losing detail in mids and shadows. It involves extracting the Lightness layer from a LAB color image, which is often a better grayscale than just going to Image > Mode > Grayscale.

1) Convert your image to LAB color; go to Image > Mode > Lab Color
2) Open your Channels Palette and select the Lightness Channel
3) Now change to grayscale with Image > Mode > Grayscale

What I do most often is open my CMYK or RGB image and make a Duplicate of it (Image > Duplicate), and view both copies side by side. Now I convert one to grayscale the conventional way, and I convert the other using the LAB method. Almost always, the LAB version is better, especially at maintaining detail in the mids and shadows. For images that are already very light and blown out, you'll probably like the conventional method because the LAB method will lighten the images even further.

You've got nothing to lose by trying both methods, running a proof and picking the best one.
 
Re: Tips and Tricks - A tip for better looking Grayscale images

Good tip. I just did this and compared images. CMYK converted image was darker. I then took that grayscale and went to Image>Adjustments>Variations. With the fine course setting two down from fine give one click to lighter midtones. Then compared the two again. They are pretty much match spot on. Funny because this is what I've always done in the past with my converted grayscale images.

Darin

Edited by: Darin on Mar 16, 2008 3:44 PM
 
Re: Tips and Tricks - A tip for better looking Grayscale images

Cool. Sounds like about the same number of clicks for you, so it may not save you any time. Especially if you're getting the same results.

Glad you shared your method, too. I Always like to hear about different approaches that achieve similar results.
 
Re: Tips and Tricks - A tip for better looking Grayscale images

For me, the Channel Mixer has been God's gift for converting to grayscale.

rich
 
Re: Tips and Tricks - A tip for better looking Grayscale images

> {quote:title=Helmet_of_Poe wrote:}{quote}
> Here's a cool trick to get (usually) better looking and printing grayscale images from CMYK or RGB images. This works best on darker images when you're concerned about losing detail in mids and shadows. It involves extracting the Lightness layer from a LAB color image, which is often a better grayscale than just going to Image > Mode > Grayscale.
>
> 1) Convert your image to LAB color; go to Image > Mode > Lab Color
> 2) Open your Channels Palette and select the Lightness Channel
> 3) Now change to grayscale with Image > Mode > Grayscale


You forgot to mention that in the 2nd step, you have to delete the other two channels.

Nonetheless, THANKS...a very helpful tip. Much favorable results going this route. :)
 
Re: Tips and Tricks - A tip for better looking Grayscale images

You're right. I should have made that more clear.

You have to click on the Lightness Channel to select it, and when you do THEN go to Image > Mode > Grayscale. This method deletes the A and B channels and changes the image to Grayscale mode.

Hope this saves a couple of steps.
 
Re: Tips and Tricks - A tip for better looking Grayscale images

Thank you for the cool tip. :) will be using it in the future!
 
Re: Tips and Tricks - A tip for better looking Grayscale images

I was given a similar trick like 10 years ago...

1. Change color mode to Lab.
2. Change color mode to Multi Channel.
3. Delete channel Alpha 3, then delete channel Alpha 2.
4. Change color mode to Grayscale.

This seemed to do a better job of maintaining more contrast with highlights and shadows as opposed to just converting from RGB or CMYK to Grayscale.

Cheers,
Jon Morgan
Hopkins Printing
 
Re: Tips and Tricks - A tip for better looking Grayscale images

We've been doing this trick since Photoshop 5 I think and yes it works very well. To select the lightness channel in the lab color hit

Cmd-1

Then convert to grayscale. We mostly print Grayscale images on 50 and 60 lbs uncoated stock at 133 lpi.

Works great! Even with 72 dpi images.

I still usually have to bring down the midtones with the curves dialog just a touch.

Edited by: Vincent_ on Mar 18, 2008 1:47 PM
 
Re: Tips and Tricks - A tip for better looking Grayscale images

Yes. It is an older trick, but I thought I'd post it after a discussion about duotones in another thread suggested simply converting CMYK > Grayscale.

I wonder if anyone else would like to see a Tips and Tricks discussion here at PrintPlanet. I'll post Cory and see what he thinks.
 
Re: Tips and Tricks - A tip for better looking Grayscale images

I think a tips and tricks page is an excellent idea!

Cheers,
Jon Morgan
Hopkins Printing
 
Re: Tips and Tricks - A tip for better looking Grayscale images

Thanks for the tip Helmet. Gives a much better result. Just sent all it to all my coworkers here...

I also think a tips and tricks page is a great idea.
 
Re: Tips and Tricks - A tip for better looking Grayscale images

Some cool methods for deriving grayscale images to be sure. Not much discussion on which grayscale ICC profile to use for the conversion however, other than image-mode-grayscale. Quick note to point out the the black ink ttonal response of your specific CMYK output device profile can be rendered as your working space grayscale profile via the "Load Gray" option and is well suited for use on grayscales to be printed via the same destination as the CMYK workingspace.
 
Re: Tips and Tricks - A tip for better looking Grayscale images

faster to simply change to lab, view the lightness channel then
change to greyscale. it will discard the a and b channels.

but this approach does not always work as well as a different
approach (green channel, adjusting the color to lighten reds, etc) so
it is only one tool in the bag.
 

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