Thank you for the responses I've received so far. It is very helpful. I have a related question:
We have old black and white photography, but now, any new photography that we have taken is in color, mostly digital. All previously existing slides, prints, negatives, etc. have been digitized. We have some faculty members that do not want color photography for their research purposes, particularly when it comes to Classical Archaeology objects such as Greek pottery. If we have all new photography done in color, and offer to give them grayscale files created from the original color photography, would they be receiving as much information as they would if we had the photography done in black and white? They are suggesting that we continue to have black and white photography done in some cases but I'm hoping that careful conversion of color photography to grayscale would contain as much, or more information than having separate black and white photography done. Marianne Weldon Fellow, The American Institute for Conservation Collections Manager of Art and Artifacts 202 Canaday Bryn Mawr College 101 North Merion Avenue Bryn Mawr, PA 19010 office 610-526-5022 mweldon at brynmawr.edu See our collection online at: Triarte.brynmawr.edu and at emuseum.net ----- Original Message ----- From: mcn-l-requ...@mcn.edu To: mcn-l at mcn.edu Sent: Wednesday, May 1, 2013 8:00:01 AM Subject: mcn-l Digest, Vol 93, Issue 1 Send mcn-l mailing list submissions to mcn-l at mcn.edu To subscribe or unsubscribe via the World Wide Web, visit http://mcn.edu/mailman/listinfo/mcn-l or, via email, send a message with subject or body 'help' to mcn-l-request at mcn.edu You can reach the person managing the list at mcn-l-owner at mcn.edu When replying, please edit your Subject line so it is more specific than "Re: Contents of mcn-l digest..." Today's Topics: 1. Color to Grayscale (Stephen Petegorsky) 2. Re: Color to Grayscale (Frank Kennedy) 3. Re: Color to Grayscale (Frank E. Thomson) ---------------------------------------------------------------------- Message: 1 Date: Tue, 30 Apr 2013 08:44:26 -0400 From: Stephen Petegorsky <petegor...@external.umass.edu> To: mcn-l at mcn.edu Subject: [MCN-L] Color to Grayscale Message-ID: <517FBCAA.1080303 at external.umass.edu> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed" Marianne - it depends how you convert from color to grayscale and how you save the converted file. If you are using Photoshop and you use a black and white adjustment layer to convert to grayscale, the bottom (or background layer) will still have the color information, and it will stay there if you save the file and all its layers as a .psd file. However, if you flatten the image, or use Mode - Grayscale from the Image menu, or use Convert to Profile from the Edit menu to change the file and then save it as a grayscale file, the color information will be lost. I think it's always best to make a copy of the original file and save that one as a grayscale file if you may need to retain the color information. -- *Stephen Petegorsky Photography* 172 North Farms Rd. Florence, MA 01062 413.586.3257 www.spphoto.com <http://www.spphoto.com> Studio hours: By appointment, Monday through Wednesday, 8:30 - 5 ------------------------------ Message: 2 Date: Tue, 30 Apr 2013 16:08:20 +0000 From: Frank Kennedy <fkenn...@nrm.org> To: "mcn-l at mcn.edu" <mcn-l at mcn.edu> Subject: Re: [MCN-L] Color to Grayscale Message-ID: <8BEC32D79947D046A6770AB52A0FE68A38558E8F at srv-mail.nrm.org> Content-Type: text/plain; charset="us-ascii" In my experience with a large archives colletion, it *does* make a difference. Greyscale is typically 256 shades of grey. Basic color at 8 bits per channel is almost 17 million shades. Where this becomes apparent is in wide areas of gradation, like a photo with the sky showing, or an expanse of wall. With 256 shades of grey, "banding" can become visible in the sky where one shade changes abruptly to the next shade - I'm sure you've seen this happen. Also, sometimes the color of the paper, ink, stains and other things can become important at an unknown future date, so maybe you want to keep that information. Once you toss the color information and detail, you can never get it back. When trying to save hard drive space, consider using 8 bits per channel rather than 16 bits per channel in color images. Makes a huge difference in file size and I personally cannot detect a visible difference, even on very high-end reproductions. -frank ------------------------------ Message: 3 Date: Tue, 30 Apr 2013 15:23:15 -0400 From: "Frank E. Thomson" <fthom...@ashevilleart.org> To: Museum Computer Network Listserv <mcn-l at mcn.edu> Subject: Re: [MCN-L] Color to Grayscale Message-ID: <6905D9194DC5B6489FA18E7E0763D974C63F4880D4 at server4.ashart.local> Content-Type: text/plain; charset="utf-8" In PhotoShop you can convert to a gray scale in a manner that keeps maximum tonal range. After saving you cannot convert back to color so that information is lost. Frank Thomson Asheville Art Museum Mailing address: PO Box 1717, Asheville, NC 28802 Street address: 2 South Pack Square, Asheville, NC 28801 828.253.3227 t 828.257.4503 f fthomson at ashevilleart.org www.ashevilleart.org Our Vision: to transform lives through art -----Original Message----- From: mcn-l-bounces at mcn.edu [mailto:mcn-l-boun...@mcn.edu] On Behalf Of Marianne Weldon Sent: Tuesday, April 30, 2013 7:42 AM To: mcn-l at mcn.edu Subject: [MCN-L] Color to Grayscale I've been led to believe that converting color images to grayscale digitally does not loose information, but have no actual 'proof' of this. Is anyone aware of any documentation or publications on this topic? Additionally, I know many people that choose to scan black and white images in color then convert to greyscale.....again...any useful data or discussions on this out there? Thank you! Marianne Weldon Fellow, The American Institute for Conservation Collections Manager of Art and Artifacts 202 Canaday Bryn Mawr College 101 North Merion Avenue Bryn Mawr, PA 19010 office 610-526-5022 mweldon at brynmawr.edu See our collection online at: Triarte.brynmawr.edu and at emuseum.net ------------------------------ _______________________________________________ mcn-l mailing list mcn-l at mcn.edu http://mcn.edu/mailman/listinfo/mcn-l End of mcn-l Digest, Vol 93, Issue 1 ************************************
