Professional flatbed scanners?

[clay harmon]

It is not contradictory when you realize that there is not a one-to-one correspondence of scene/subject density range and transparency (or negative) density ranges.

That is where the idea of gamma or CI (contrast index) is valuable. Most people process black and white negative film to a gamma/ CI (not the same, but close enough for the purposes of this explanation) of 0.55. This basically means that for the main part of your response curve, a scene luminance change of 1 stop (doubling or halving of intensity) produces a 0.55 stop change on the negative's density.

Slide film, however, has gamma/CI in the range of 1.5-2.0. This means that a one stop change in subject luminance produces a 1.5-2.0 stop change in the slide density value. It is 'contrasty', to use the vernacular expression for this. Check out the slope of the graph for Ektachrome 100 for instance:

http://www.kodak.com/global/en/profe...002_0787ac.gif

See how steep it is? That means that a 1 stop change in subject luminance produces a 1.6-1.8 change in the density on the transparency film.

This sounds contradictory.



If I understand you correctly you are speaking of dynamic range compression; i.e. transpparency contains more information in a smaller dynamic range?

I thought Dmax was about being able to detect information in dense areas on a negative or transparency while Dmin is the ability to detect information in low density areas. Of course chrome has no nuetral transparent space that is not filled with some form of color (except B/W transparecies of course) Again I am a total newbie here. I ordered a recommended scanning book from Amazon to continue my own education.

Joe

[Frank Petronio]

The kindly old Kodak film researcher told me that in the 50s as color film was being heavily R&D'd, they expected professional large format photographers would shoot color neg and make carefully crafted color prints for reproduction, since the would have more control, retouching, etc.

They didn't anticipate how freaking lazy professional photographers really are.

And that is why they shot tons of chrome film for fifty years....

From a production, film handling, and quality POV I think Kirk is right on in persuing a high end flatbed.

Personally I wish someone would make a $1500-2500 flatbed that had professional build quality and with slightly better specs than the current Epson 750. I think a lot of us would jump at that, I got burned on a Mircotek and the Epsons are OK but I suspect they vary a lot from unit to unit.

[Bruce Watson]

This sounds contradictory.

Yet, it's not. Don't confuse the Subject Brightness Range (SBR) of the scene in question with the density range on film. Trannies are capable of recording a restricted SBR, depending on the film of course. A range of from 4-6 stops of SBR maybe. Tranny Dmax can be as high as 3.6 or higher. The Kodak calibrated density target only goes to 3.6; it's difficult to measure accurately above that.

Consumer flat bed scanners have difficulty reading through that large Dmax to record the shadow detail. The typical complaint about trannies and consumer flatbeds are noise in the shadows or a complete lack of shadow detail. High end flatbeds have less problems with trannies, and of course drum scanners have very little problem with trannies.

If I understand you correctly you are speaking of dynamic range compression; i.e. transpparency contains more information in a smaller dynamic range?

It's not compression. It's translation. Tranny film translates a smaller SBR into a large density range. Negative films translate a larger SBR into a smaller density range. There is no need for a one-to-one correlation between SBR and density range.

It's helpful to remember the design function of tranny film is to be the final output -- one puts it into a projector and projects light through the tranny onto a screen. The tranny therefore has to have the ability to create an image with a convincing white (lets all the light though) and a convincing black (blocks all the light).

Negative film, OTOH, is designed to be an intermediary. It's used to capture the SBR of the scene in such a way as to make it easy to translate the captured information to photographic paper so that the final output is a print. This doesn't require the high density of the tranny -- in fact, high density is harder to work with when making prints.

[Brian K]

The kindly old Kodak film researcher told me that in the 50s as color film was being heavily R&D'd, they expected professional large format photographers would shoot color neg and make carefully crafted color prints for reproduction, since the would have more control, retouching, etc.

They didn't anticipate how freaking lazy professional photographers really are.

And that is why they shot tons of chrome film for fifty years....

Frank, it's not a matter of being lazy, it's simply smart business to shoot chromes versus color neg if you are shooting work for repro. Unlike a wedding photographer where the print is the final result of the photograph, for a commercial photographer it's usually mass reproduction that is the ultimate use.

A commercial photographer gets paid to shoot. It may take a day or days to complete the shoot. Does it make commercial sense for a busy photographer to turn away assignments in order to make color prints? Do you think that most clients are willing to pay hundreds or thousands of dollars a day to have a photographer print color prints from color negs? (I'm talking traditional processes here, not hitting "Command P and going for coffee). It is simply more efficient for the photographer, and cheaper for the client to work with color chromes. It's business after all.

[jetcode]

Thanks for the explanations everyone. Material sciences. The terms are familiar and now I get to learn and engage the implications. I discovered why I had to adjust my scanned neg for white. It's underexposed by a stop or so and has relatively low contrast. My guess is the scanner is already calibrated within reason and I have to tighten the control over exposure and processing. It's a fairly steep learning curve but I'm not starting from scratch. Rather then plague the forum with beginner questions I need to research and learn the craft. As far as becoming a "pro" scan house; not. I'm more interested in my art then being a service bureau. When I have some experience and feel comfortable with the tools and processes I will open the door to that possibility on a limited basis and most likely local.

Thanks again,
Joe

[Asher Kelman]

Frank, it's not a matter of being lazy, it's simply smart business to shoot chromes versus color neg if you are shooting work for repro. Unlike a wedding photographer where the print is the final result of the photograph, for a commercial photographer it's usually mass reproduction that is the ultimate use.

Maybe the real reason is that trannies can be simply put on a lightbox and the art department and client can choose the impressive beautiful sexy image in seconds raher than have to see a flat print.

Asher

[sanking]

BTW, to the best of my understanding, all of the current high end flatbeds, including the EverSmart Supreme, Fujis, IQSmart, etc, use the same Kodak 8,000 element CCD. Therefore, any differences in performance would be due to lens quality, how the lens sees the scanned material, stitching type, etc.

Effective resolution of EverSmart scanners is on the order of 90-95% of maximum potential optical resolution. This is a very high %, and results from XY stitching technology, only present in EverSmart and IQSmart scanners. Some very experienced users on the Scan Hi-End forum claim that the
Rodenstock lens of the EverSmart gives sharper results than that of IQSmart scanners, but I don't know if that is true. I do know for a fact that the effective resolution of my EverSmart Pro scanner is about 95% of optical maximum. Optical maximum is 3175 ppi, and tested effective is well over 3000 ppi, and that is over the entire scanning area of 12X17".

The major problem with the high end flatbeds is that they are huge. EverSmarts weigh about 160 lbs and take up a space of about 32X29X13".


Sandy King

[Brian K]

Maybe the real reason is that trannies can be simply put on a lightbox and the art department and client can choose the impressive beautiful sexy image in seconds raher than have to see a flat print.

Asher

Asher, I don't think it's about the client seeing a more impressive image, afterall what really matters is how it looks in print, but the faster turn around might be a factor for them. Shooting chrome was the industry standard when I first started working in the commercial area. In 25 years in the business I can't recall ever shooting color neg film.

Sandy, the IQsmarts use a 10,200 element tri linear ccd. The top optical resolution on the IQSmart 3 is 5500 ppi.

[David A. Goldfarb]

For print media, transparencies are certainly easier to edit, and they are self-proofing, in that the press proofs can always be compared to the transparency. A negative always requires interpretation.

[Brian K]

For print media, transparencies are certainly easier to edit, and they are self-proofing, in that the press proofs can always be compared to the transparency. A negative always requires interpretation.

David a color transparency requires color calibration as does a color neg. Color transparency film always required that the emulsion be color tested and color correction added prior to exposure. With color neg a color chart or gray scale would need to be included in the photo, or in a test exposure to be used to set and calibrate the color balance for a final print. So in either case the photographer is interpreting or setting the color balance.