What should a high quality drum scan look like?

[big_ben_blue]

Question to all the drum scanner folks here:

What should a high quality drum scan from a 4x5 slide nowadays look like in terms of size, dimensions, bit depth, colour space,...

Is there an "industry standard" in what to expect when getting a scan done by a pro lab?

There's a little back story to my asking. I am doing a lot of photoshopping for a large museum, and lately they are digging out slides from their archive (nothing antique or spectacular, just regular stuff done over the years). However the drum scans they got done by a pro-lab look not exactly awe inspiring to put it mildly. I was rather surprised to find the images in 8 bit CMYK mode (about 60mb in size) with questionable tonality (contrast and sharpness all the way up, clipped highlights and shadows, topped with an very noticeable cyan cast). The pics also contained a number of weird scanning artifacts (some looked like tartan squares in a regular pattern; other pics had a distinct halo like "glowing" of the subjects against a dark background).

[Larry Gebhardt]

They should not look like you describe for modern printing. My 4x5 drum scans are done at ~3000dpi and 16bit (actually 12) RGB. The file size is about 1GB. There is no clipping if the negative or slide is properly exposed, and even then the clipping will be on the film, not from the scan.

[Lenny Eiger]

Question to all the drum scanner folks here:
What should a high quality drum scan from a 4x5 slide nowadays look like in terms of size, dimensions, bit depth, colour space,...

A drum scan should be perfectly sharp. 16 bit RGB, unless you have requested they perform some sort of b&w conversion for you. I scan 4x5's at 4000 ppi, which yields a 1.7 Gig file. 20,000 pixels across the longest edge, which means you can do just about anything you want...

This is my personal bias. Some people like to charge by the megabyte and customers have to make choices of how much of a scan they want. When I started out I wanted to deliver only great scans, so I always deliver the full size - unless people specifically ask for less. The price is the same either way.

Hope this is helpful.

Lenny

EigerStudios
My iPhone App shipped! Check it out in the New Products forum here or
http://www.phototoolspro.com

[Frank Petronio]

Twenty years ago that is how a lot of mid-level drum scans looked. Quality was sufficient but not so great. Everything was 8-bit CMYK and over-sharpened. It printed OK but not great. Scans from slides and color neg were usually the worst.

Once print shop customers got Macs and started being able to work on files themselves, the middle-ground actually improved. But unskilled and sloppy work continues....

[Bruce Watson]

What should a high quality drum scan from a 4x5 slide nowadays look like in terms of size, dimensions, bit depth, colour space,...

Depends on what's specified by the customer. Often this is tied directly to how much the customer is willing to pay. Bigger files take more time on the machine, and time is money, yada yada yada.


Is there an "industry standard" in what to expect when getting a scan done by a pro lab?

None I know of.


There's a little back story to my asking. I am doing a lot of photoshopping for a large museum, and lately they are digging out slides from their archive (nothing antique or spectacular, just regular stuff done over the years). However the drum scans they got done by a pro-lab look not exactly awe inspiring to put it mildly. I was rather surprised to find the images in 8 bit CMYK mode (about 60mb in size) with questionable tonality (contrast and sharpness all the way up, clipped highlights and shadows, topped with an very noticeable cyan cast). The pics also contained a number of weird scanning artifacts (some looked like tartan squares in a regular pattern; other pics had a distinct halo like "glowing" of the subjects against a dark background).

Sounds like a combination of a customer now knowing what they want and therefore not specifying the job well, a pro lab not doing a very good job at scanning, and a scanner that is perhaps not in tip-top shape.

I used to drum scan for other people. What I used to try to deliver was a scan that contained everything on the film (unless instructed otherwise), from black to white -- no clipping. RGB. 16 bits/channel. No sharpening at all. This is what I called a raw scan -- it looks somewhat flat and not very contrasty.

The reason for this is fairly obvious. It's fairly easy to clip white and black points to taste, to increase contrast to taste, to increase saturation to taste, etc. IOW subtracting image information from a scan file is easy. OTOH adding image information that wasn't captured into the scan file is very difficult indeed.

[big_ben_blue]

Thanks guys. That's exactly the info I needed. It pretty much confirms my own thoughts; but I didn't want to jump the gun and come down too hard on the guy who did the scans. I'll redirect my client to this thread.