Grayscale images on a printing press?

Ok, I've researched this and I think I have the answers, but I just want to be sure by running this by those of you who've done it:

I shot some pictures this week for an essay my brother-in-law is writing. This essay will be published in a book. He said all his publisher told him was that they wanted the images to be 300 DPI Grayscale. Easy enough. So, I've got all these 300 DPI grayscale tiffs... but what about bit depth and color space? I'm inclined to keep them 16 bit so the publisher has more information to work with, but is that what they prefer? Also, these things are saved in sRGB... is that the correct color space to send to a publisher? Keep in mind these things will be published (I assume) on a standard book press.

Thanks for any help... I just don't want my brother-in-law to send in pics that reflect badly on him, by being in the wrong format.

Joe

Ask the publisher what format they want. Also be aware that black and white and greyscale aren't the same - greyscape is just a desaturated image, black and white is often processed a bit. Have a look at this thread, get that pbase magazine, there's a good article in #3 or #4 on it.

Thanks Tim... yeah, I almost made that mistake about B&W vs. Grayscale. I started to do nice B&W conversions on these images, then realized my mistake. They are all Grayscale conversions now. I was hoping there'd be a standard for this, but if not I'll have him check.

The publisher might be referring to duotone or tritone images, used for a black & white printing press. Ask him.

The thing that really sets grayscale apart from RGB is the fact that the file is one third the size, since each pixel is represented by a luminance value only.
Which is probabably of no concern, but I am curious to know what the printer wants.

As a prepress tech in a printing company my advise is to ask the printer. They should be more than happy to tell you exactly what they want. We only can wish that our customers would ask us before sending. It would save a lot of delays. You would be amazed at some of the things we get sent as (supposed) print-ready files. If the printer has a website they may have the info there.

I'm a print buyer for a textbook publishing company and you have the files set correctly. Set image..mode..grayscale @300 saved as tiff's. A DTP program will not take jpegs.

One other thing, the book will probably be a 1 color job, meaning black only. You can not have a duotone or a tritone in a one color job. That would be a two or a three color print job.

Thanks Chris... yeah, the publisher specified grayscale, so I would be surprised if he actually meant duotone or something. Do you prefer 8 bit or 16 bit images, and is sRGB a good color space? I will check with the publisher before sending, but can't do that till Monday morning, and he wants them Monday morning, so it would be nice to have them set up in what is probably the correct format before then, so I can just confirm and send.

Joe

if this is greyscale its neither a srgb or adobergb space. those are color gamut space. Greyscale are halftone (black & white)... They are counted as percentage. 20%, 30%...etc... You need to find out from the press normal US is 20%.

8 or 16 bit, doesn't matter. Color space, doesn't apply to this. As long as you have them as grayscale tiffs @300, your good to go.

That's quite correct Chris. 300dpi at 100% size. A black and white image can be achieved many ways, but convert to greyscale when you are happy with the look. There is no colour data and one, single black channel. An rgb profile does not apply. The files have been requested in greyscale, not for visual appeal, but because they are only printing black.

Professional DTP programmes, can in fact, use jpegs. Quark Xpress has always had that capability. Even if you are using a high quality setting, it will allow you to email then rather more easily as there size will be greatly reduced.

Graham

It might take jpegs, but it will also take RGB images and True Type fonts. None of which are used for print output. If I sent a job to a printer with jpegs in it, they would request new files.

But you actually stated that a dtp programme will not take them, so I just wanted to correct you, in case you actually believed it to be fact.

I run a design consultancy and do my own repro. I avoid truetype fonts as I find type 1 more reliable. I don't use rgb images for cmyk. But I do regularly use jpg images. I often send my repro files to my clients, via email, for their own printing and have no problems. It would cost me money if I made mistakes, so I wouldn't do it if it were in some way wrong.

You will have to ask the repro house why they have taken that stance with you regarding jpgs. I would be interested to hear their answer.

Graham

Oh, I see... Looking at the history of these images, I converted them to Grayscale, then applied a little sharpening which converted them to sRGB. I'll resave as grayscale.

Thanks for the help...

Graham,

We deal with about a dozen printer's and none of them take jpeg's in the files. I called a couple of them and talked to the prepress manager's, both said it was due to the compression on the jpegs. When the file is preflighted they only see if it's at the proper resolution, not what compression level was used. As you know, a tiff is losless so they don't have to be concerned with the compression level. If a high res color proof is made you would see any jpeg artifacts, but it's cost prohibitive to make high res proofs for every page of a 4/4 or a 1/1 book.

I'm glad to see you don't use TT fonts, although some of the newer rips will now take TT fonts.