Photoshop greyscale conversion provides an arbitrary translation of a color scene. It uses the same percentages (approx 30% red, 59% green, 11% blue - I've seen somewhat different figures, but they're all about the same) regardless of the image and the colors it contains. A big drawback to using the conversion is that it just smashes all three color channels together, and should there be a problem with any given channel - if a channel is damaged or excessively noisy - those artifacts and problems go into the greyscale conversion as well. There's no preview and you have no control over the percentages and the final outcome.
I believe that your professional retoucher is shortchanging her clients. There is no one true way to make conversions, no best way. A truly skilled retoucher might be familiar with several techniques, and will choose the one best suited to the image and desired outcome. While it's true that some techniques may be complicated and time consuming (such as selecting and splitting channels), and offer minimal advantages over a simpler technique for some images, there will be times when knowing how and when to use such a technique is appropriate. What is a "theoretically perfect B&W film?" Shel "You meet the nicest people with a Pentax" > [Original Message] > From: Rob Studdert > On 31 Oct 2005 at 17:50, Paul Stenquist wrote: > > > PhotoShop grayscale conversion provides an accurate translation of a > > given color scene. It's quite close to what the values would have been > > if shot without filtration. > > IOW as if shot was made on a theoretically perfect B&W film?
