What am I doing wrong?

[Ben R]

I've been trying to get a handle on scanning my polaroid negs with my new Epson 4990. Here is the photo taken from my front drive (sorry it's so boring!), the areas marked by the squares are soft, almost like they're out of focus. The rest of the photo front to back is pin sharp from the rest of the forground to the far background. The photo was taken using a 90mm Caltar focused front to back using Hansma and stopped down one stop further even to f22. No movements other than some rise.

I've tried using the epson carrier and taping the neg to the glass, emulsion up and emulsion down, same difference each time, the bush on the right hand side is horribly sharp (and the buildings behind) as is the fir tree on the left but the areas marked look OOF. Same thing in the foreground, the pebbles to the right are crisp and defined, those in the marked area are a mush.

I'm new to LF in general but I can't see technique wise what I could be doing wrong at the shooting stage that would cause this effect. Any ideas?

Many thanks,

[M Brian Mills]

If the neg is truly flat on the glass when scanning then it is an issue with the negative itself.

I haven't used Polaroid film much but my guess in this case would be that the portions that appear to be out of focus would be due to the film not being absolutely flat in the film-holder when the image is created. This seems a possibility since it is the items near the middle of the image that appear to be OOF--as if the film has a bit of an arch to it with the sides being closer to the focus-plane where the middle of the neg might be arching into the camera more.

[Ben R]

Would stopping down further help, is there something I should do different which would solve the problem?

[M Brian Mills]

I'm going to have to defer to someone who uses Polaroid film more than I do.

I know that some people have gone to the lengths of using double-stick tape to make sure that their film is flat in the holder when the image is made. You could try this.

My feel is that this has something to do with Polaroid film and might be an inherent characteristic of it.

[Tom Westbrook]

Do those areas on the negative look sharp with a loupe? Most scans are a bit soft with my 4990, but its even across a negative regardless of type. I put a piece of glass on top of mine--maybe that might help if the neg isn't totally flat.

[Scott Davis]

Polaroid type 55 is about 1-2 mm larger in each direction than a standard 4x5 transparency or negative. They don't fit well in the 4x5 holder for the 4990. They will tend to buckle. Also, T55 is a rather fickle film and doesn't lay terribly flat even in a traditional enlarger. That can be worked around by stopping the lens down; however, you can't do that with a scanner. If the negative is sufficiently out-of-plane in spots, they'll go out of focus with the scanner.

[Ben R]

I've tried taping it super flat against the glass of the scanner, it didn't help. I'm going to try the same photo again today when I get a chance and stop down further, maybe be more gentle taking the paper slide out and give the neg time to settle before taking the photo, see what happens.

[j.e.simmons]

Search for threads on the 4990 - mine seems to focus a bit above the glass, and other folks have reported the same. I've found that sandwiching my negatives between two sheets of non-glare picture frame glass solved both my focus and flatness problems. It's been discussed here before.
juan

[Frank Petronio]

Under normal conditions, f/22 w a 90 should be super sharp.

And, while you might have to trim the edges of the Type 55 neg to fit into the Epson holder in order for the film to lie relatively flat, you should be able to get a decent scan with the stock scanner and holder. Maybe not optimal, but pretty darn good...

So loupe the film with a 8x loupe to see it is the film.

If the film is sharp, try a different scanner.

If the film isn't sharp, try shooting some straight on, no movement centered shots to make sure you everything neutral and your technique is OK, the film holder is OK, etc.

If the scanner isn't sharp, do a comparision with a known good scanner... and maybe get a different one.

[Ben R]

I've shot another sheet, same place, lets see what happens once it's dried. The focus problem is only in the marked areas which seem to assume a problem with the film if the same problem is seen when I tape the film against the scanner or use the epson holder (after trimming). Yes the holder is sharper but I'm still seeing that the same part of the image is softer with both scans or even scanning with both the emulsion and shiny side up, same difference in sharpness with those areas. Even tried it at different points on the glass, same thing.

EDIT - Just had a look at it under the loupe, 7X magnification, I've stared at it till my eyes feel like they're popping out but I can't see the OOF areas that I'm seeing in the scan. It doesn't help that they are not completely soft, just not anywhere near as razor sharp as the rest of the image, almost impossible to see that kind of difference under a loupe.