Topic: Printing with Gray Working Space ? (Read 3374 times)

ThePhotoDude · « **on:** June 10, 2009, 03:54:14 pm »

I've been sent a bunch of images to print for a client, but the working space they have converted them to is Gray - Dot Gain 20%.

I'm really not sure how to process this correctly. The skin tones of the subject look kinda dark to me or is that how the photographer intended? Or is there something he should be or I should be doing?
Has the image been damaged be converting to this 'Dot Gain' space?

Should I ask him to send me the images again in RGB?
I really don't want to print this wrong as there is a whole bunch on fine art paper.

Help!

Thanks - BTW, I print from Qimage FWIW.

ThePhotoDude · « **Reply #1 on:** June 11, 2009, 05:04:58 pm »

Sorry for the bump, I am really needing to understand this.

If my customer has converted to this Gray Dot Gain 20% space, is what I am seeing on my screen in CS4 how he wants the photo to look?

Thanks

Wayne Fox · « **Reply #2 on:** June 11, 2009, 05:49:37 pm »

Not sure I can be of much help here since I'm unclear why anyone would use this space for images headed to an inkjet printer.

However, I would guess that if you printed the file through your normal printer profile the result would be very close to what appeared his screen when he did the conversion, it seems logical that is what he is expecting to see.

Sounds like a quick phone call to the customer may be in order to try and understand the reason for his choices.

Personally I would think results would be better if he did a B&W conversion and then sent the file in an RGB working space.

TylerB · « **Reply #3 on:** June 11, 2009, 08:14:33 pm »

if he converted them to 20% gray intentionally (a prepress standard by the way) and did so viewing them in a color managed app like PS, on a properly color managed monitor, you have to proceed under the assumption that they look as he intended. A quick conversation would help, asking the above. They have to be converted to your output profile from something, and if they are B&W images, DG20% is as good as any other.
Tyler

AaronPhotog · « **Reply #4 on:** June 12, 2009, 12:07:54 am »

Photodude,

If you are using Qimage, then you must be using a Windows machine. Is your client using a Mac? If so, then what you think looks too dark, is most likely darker and more contrasty than what he is seeing on his screen (unless he has changed his default gamma from 1.8 to 2.2). I agree that the use of the good ol' Photoshop tool, the telephone, is in order.

Good luck and Aloha,
Aaron

tived · « **Reply #5 on:** June 12, 2009, 02:09:12 am »

Quote from: ThePhotoDude

I've been sent a bunch of images to print for a client, but the working space they have converted them to is Gray - Dot Gain 20%.

I'm really not sure how to process this correctly. The skin tones of the subject look kinda dark to me or is that how the photographer intended? Or is there something he should be or I should be doing?
Has the image been damaged be converting to this 'Dot Gain' space?

Should I ask him to send me the images again in RGB?
I really don't want to print this wrong as there is a whole bunch on fine art paper.

Help!

Thanks - BTW, I print from Qimage FWIW.

Hi,

You can print them as you would any other, but if I were you I would print a Step-wedge together with one image and check to see when you first see details in your blacks in the same color space or in aRGB...
Make the necessary adjustments...print again, and see if it is giving you the output you are expecting.

The Gray working space as noted by others is usually for a press.

Let us know how you go.

Henrik

ThePhotoDude · « **Reply #6 on:** June 17, 2009, 08:38:24 am »

Just an update for anybody who cares,

Thanks to everyone who replied here ... I think the most important thing was understanding what Dot Gain is for, and that is offset printing, not inkjet.

Yes I phoned the customer, they didn't know what I was talking about regarding the colour space, he must have converted to that accidentally. The images were too dark, he was using an uncalibrated laptop screen.

We modified the curves in the images bumbping up the mid tone brighness and all is well.

Thanks!

digitaldog · « **Reply #7 on:** June 17, 2009, 08:47:29 am »

Conversions to gray with gamma are intended for output to a display. Conversions to dot gain are intended for output to a printing device with that dot gain. So the question is, why did he/she convert to a 20% dot gain? Have to assume someone knows that's the proper printing conditions for the output (but of course, this could be wrong).

ThePhotoDude · « **Reply #8 on:** June 17, 2009, 08:54:15 am »

Quote from: digitaldog

Conversions to gray with gamma are intended for output to a display. Conversions to dot gain are intended for output to a printing device with that dot gain. So the question is, why did he/she convert to a 20% dot gain? Have to assume someone knows that's the proper printing conditions for the output (but of course, this could be wrong).

When I asked him why he converted it to 20% dot gain, he didn't know what I was talking about, so I assume he is inexperienced in Photoshop and just clicked random things. What a headache for me however, not wanting to show my own ignorance about the subject, which is why I came here for some ideas!

AaronPhotog · « **Reply #9 on:** June 17, 2009, 08:04:09 pm »

[attachment=14619:BWSpaces.jpg]

PhotoDude,

The curves for Grey Gamma 1.8 and Dot Gain 20% are very similar (click on the 51 step tablet plot of assigned profiles attached - higher numbers are lighter, 0=black, 255=white). He selected it because it looked right to him on his uncalibrated laptop (Again, chances are it's a Mac or something set to look like one).

When you got the image file, it looked wrong because your gamma is probably pretty close to 2.2. So the same numbers look darker and more contrasty. If he had selected 30% dot gain, it would have been mostly parallel to your gamma 2.2, and a little lighter looking on your machine (it seems counter-intuitive, but that's how it is), except for the dark grey values, which would have been a bit merged on your machine. Watch that you don't lose low value separation in this scenario.

A friend often sends me files to print on my inkjet that are in the dot gain 20% space because he had gotten the scans made by a service bureau, which assumed a roughly default press rather than an inkjet. I do the same thing you did, and yank up the curve and then apply some other image-specific adjustments. It works fine, as you've experienced. Oh, and if he doesn't send me dot gain 20%, then it's grey gamma 1.8 (he uses a Mac), so, again, I have to adjust accordingly.

Glad you used the phone and everything worked out well.

Aloha,
Aaron

Ken Bennett · « **Reply #10 on:** June 18, 2009, 10:09:42 am »

Here's one idea about what might have happened.

Your client had is color settings on North American General Purpose or North American Prepress. Both of those use Dot Gain 20% as their default grayscale profile. He then chose "Image > Mode > Grayscale" from the menu bar. That would explain both the color profile and the dark skin tones.

Author Topic: Printing with Gray Working Space ? (Read 3374 times)