[filmscanners] Re: Difficult scan problem
That's a good idea and one I should probably have thought of. I think my brain is turning to mush comparing all these scanners etc. ;-) I will check to see if there is a range of values between 210 and 255. I will try and use the built-in ColorSync calibration on the Mac to get a better image but the dealer is a bit touchy about doing things to his monitor (although he should thank me if the calibration is wrong). Thanks for the advice. Simon - Original Message - From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, April 16, 2002 3:32 AM Subject: [filmscanners] Re: Difficult scan problem > On Mon, 15 Apr 2002 23:51:20 +0100 Simon Lamb ([EMAIL PROTECTED]) wrote: > > > > > When I scanned the image I found that all pixels from about 210 to 255 > > were > > showing as black and I could not get any detail to show, even though I > > know > > it is there from a scan done on a Sprintscan 120. The histogram shows > > that > > the detail should have been there. > > The fact that there are pixels of values 210-255 says there is a range of > luminosities, and if you can't actually see them, to me it suggests a > problem with monitor calibration on the system. But check : what happens if > you run the PS eyedropper over the pixels which look black, do the > luminosity values change? > > Regards > > Tony Sleep > http://www.halftone.co.uk - Online portfolio & exhibit; + film scanner info > & comparisons > -- -- > Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' > or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body > Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Difficult scan problem
>I have used col neg (Superia and other Fuji mostly) in various >fluorescents and it copes wonderfully with no camera filtration. While I have found this to be the case as well with normal subjects wherein the film was printed via traditional wet photographic methods rather than via scanning and outputting to monitor and/or inkjet. The poster did not say how the output was to be produced (e.g., on a monitor, inkjet, or something else). Since there are various types of fluorescent tubes that can generate a variety of color casts, I would suggest that one would probably need some information on what type of tube is being used in the microscope lamp and what sorts of luminescences it in combination with the subject generate that the film may see and register that would be out of gamut for digitalization, for monitor color spaces, or for printer color spaces to determine if it indeed can be digitally reporduced as it appears on the transparency or on the photographic prints from the negatives. But this is just mere speculation on my part at this point given that most of my familiarity with the products of photomicroscopy with traditional photography has involved only black and white films and radiographs that ppeople from the local University bring me to process, proof, and/or print via traditional wet dorakroom methods. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of [EMAIL PROTECTED] Sent: Monday, April 15, 2002 9:47 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Difficult scan problem On Mon, 15 Apr 2002 20:30:13 -0500 Laurie Solomon ([EMAIL PROTECTED]) wrote: > Tony, what if the "constant colour temp lightsource" is a fluorescent > discontinuous light source such as what he has said was the light source > for > the microscope; will what you suggest still hold? I have used col neg (Superia and other Fuji mostly) in various fluorescents and it copes wonderfully with no camera filtration. Unless the microscope lamp is very weird it should be possible to get good results. I haven't tried it of course, but I use the eyedroppers as described for colour correction with just about every colour neg I scan. Usually I use Vuescan White Balance as a starting point, save in 16bit, then do this in PS. PS Auto levels is frequently very wrong and I seldom use that. With crystals, mostly there is going to be a problem finding anything in the image which is a mid-ish-grey to use the midtone eyedropper on. But fixed exposure and illuminant remove the variables, so provided a decent set of corrections can be obtained and saved using an image which does contain a neutral grey, merely applying the saved levels adjustments should give a good result with all images from this setup. Close enough that all that may need doing would be limited to overall gamma, perhaps contrast, and maybe tweak the hue and saturation a little on some subjects. Oddly enough, over 30yrs ago I had a maths teacher whose hobby was photomicroscopy of crystals. He used (Agfa) colour neg and produced awesome 20x16's. It's worth persevering here I think. Regards Tony Sleep http://www.halftone.co.uk - Online portfolio & exhibit; + film scanner info & comparisons Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Difficult scan problem
On Mon, 15 Apr 2002 20:30:13 -0500 Laurie Solomon ([EMAIL PROTECTED]) wrote: > Tony, what if the "constant colour temp lightsource" is a fluorescent > discontinuous light source such as what he has said was the light source > for > the microscope; will what you suggest still hold? I have used col neg (Superia and other Fuji mostly) in various fluorescents and it copes wonderfully with no camera filtration. Unless the microscope lamp is very weird it should be possible to get good results. I haven't tried it of course, but I use the eyedroppers as described for colour correction with just about every colour neg I scan. Usually I use Vuescan White Balance as a starting point, save in 16bit, then do this in PS. PS Auto levels is frequently very wrong and I seldom use that. With crystals, mostly there is going to be a problem finding anything in the image which is a mid-ish-grey to use the midtone eyedropper on. But fixed exposure and illuminant remove the variables, so provided a decent set of corrections can be obtained and saved using an image which does contain a neutral grey, merely applying the saved levels adjustments should give a good result with all images from this setup. Close enough that all that may need doing would be limited to overall gamma, perhaps contrast, and maybe tweak the hue and saturation a little on some subjects. Oddly enough, over 30yrs ago I had a maths teacher whose hobby was photomicroscopy of crystals. He used (Agfa) colour neg and produced awesome 20x16's. It's worth persevering here I think. Regards Tony Sleep http://www.halftone.co.uk - Online portfolio & exhibit; + film scanner info & comparisons Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Difficult scan problem
On Mon, 15 Apr 2002 23:51:20 +0100 Simon Lamb ([EMAIL PROTECTED]) wrote: > > When I scanned the image I found that all pixels from about 210 to 255 > were > showing as black and I could not get any detail to show, even though I > know > it is there from a scan done on a Sprintscan 120. The histogram shows > that > the detail should have been there. The fact that there are pixels of values 210-255 says there is a range of luminosities, and if you can't actually see them, to me it suggests a problem with monitor calibration on the system. But check : what happens if you run the PS eyedropper over the pixels which look black, do the luminosity values change? Regards Tony Sleep http://www.halftone.co.uk - Online portfolio & exhibit; + film scanner info & comparisons Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Difficult scan problem
michael shaffer wrote: > > > Most likely a white balance problem, and the fact neither software can > properly determine the "color of white" for a microscope illuminated > subject. What Maris suggests should work ... that is, Vuescan's advanced > techniques should allow you to color correct a normal negative ... fix the > "mask correction", and then fix the "color correction". These settings > could then be used to scan the problem negs. We have played with all the colour controls in Vuescan and still can't get a satisfactory result so the scan is sent to PS and its altered in there. Rob Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Difficult scan problem
Rob writes ... > The negs are taken through a microscope and are of rocks. > Some or every second one has been lit by fluorescence light > source and the base colour comes out a golden yellow and > the other colours are sort of fluro greens, greens to blacks. > > When the scans are done either in Nikon Scan or Vuescan they come > out towards magenta tones. > ... Most likely a white balance problem, and the fact neither software can properly determine the "color of white" for a microscope illuminated subject. What Maris suggests should work ... that is, Vuescan's advanced techniques should allow you to color correct a normal negative ... fix the "mask correction", and then fix the "color correction". These settings could then be used to scan the problem negs. cheerios ... shAf :o) Avalon Peninsula, Newfoundland www.micro-investigations.com (in progress) Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Difficult scan problem
I have a difficult scan problem : ( The negs are taken through a microscope and are of rocks. Some or every second one has been lit by fluorescence light source and the base colour comes out a golden yellow and the other colours are sort of fluro greens, greens to blacks. When the scans are done either in Nikon Scan or Vuescan they come out towards magenta tones. Having tried to reverse this with the controls in either programme there is insufficient range and look yuck. I use auto exposure auto balance then try to re-balance with the control panel before the scan. I have been correcting them in PS but don't seem to replicate a tranny image of the subject matter. ( if tranny film is used in place of neg film). Its like chasing my tail around either way. I have suggested that tranny film is used in place of neg material but photographic prints are some times required. Can anyone suggest another technique that will give me a closer colour scan than what I'm getting now. Thanks Rob Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
