Page 1 of 3 123 LastLast
Results 1 to 10 of 30

Thread: Epson V800 Calibration Area

  1. #1

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Epson V800 Calibration Area

    When the scanner is turned on or a preview is performed in Vuescan, the scanner appears to do a self calibration routine. Dows anyone know what it is calibrating.

  2. #2

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 Calibration Area

    As far as I can tell, Each sensor is being "reset" so that "1" equals the maximum intensity, so the output is a "digital white" 1,1,1.

    Using vuescan you skip this step entirely.

  3. #3

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Re: Epson V800 Calibration Area

    Quote Originally Posted by Ted Baker View Post
    As far as I can tell, Each sensor is being "reset" so that "1" equals the maximum intensity, so the output is a "digital white" 1,1,1.

    Using vuescan you skip this step entirely.
    How can you skip the step please Ted

  4. #4

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 Calibration Area

    Quote Originally Posted by IanBarber View Post
    How can you skip the step please Ted
    Just skip the preview button and just press scan only, that is the most compelling feature of viewscan IMHO. I have a profile for each type of film i scan. So if a have 20 sheets of HP5. I can scan that in 10 passes of the sensor which should take 80 minutes... Everything including the exposure I want for the FP5 film base, cropping, resolution is already in profile. So no preview required of anything.

    The per pass calibration still occurs BTW, just to correct parameters loaded by vuescan.

    Its impossible to figure out exactly what the scanner does, but by looking at the source code of the driver, etc and how it responds some reasonable assumptions can be made.

  5. #5

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Re: Epson V800 Calibration Area

    Ted, I assume that you are using a holder which always ensures the negative is in the same place for your profile to correctly place the boundry box around the negative.

    I personally place the negative on the wet mount holder but do scan it dry. I probably could make a template or something showing me where to put the negative and then like you create a fixed profile

  6. #6

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 Calibration Area

    Quote Originally Posted by IanBarber View Post
    Ted, I assume that you are using a holder which always ensures the negative is in the same place for your profile to correctly place the boundry box around the negative.

    I personally place the negative on the wet mount holder but do scan it dry. I probably could make a template or something showing me where to put the negative and then like you create a fixed profile
    or just select the whole area, or a large enough area to be sure. The scanner always scans the whole width, if I have two 4x5 images I still just scan in one complete pass. I wrote my own software for 35mm and 120 to digitally cut the film. For 4x5 just scan the whole area and cut it "photoshop" much less fiddling around. My software would work for 4x5 if I adjusted it.

    You just need the exposure to be set to suit the film base, or (you skip that consider the film base to be a density of 0),

    I can scan 6 rolls of 35mm in 1 hour at 2400dpi, on my old 4990

    The only problem with this approach is 4Gig tiff file limit imposed my most if not all scanning apps (including vuescan) This might be a problem with colour, if like to scan beyond 2400dpi.
    Last edited by Ted Baker; 15-Aug-2019 at 07:59.

  7. #7

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Re: Epson V800 Calibration Area

    Ted, are you scanning for a RAW output or just a regular tiff

  8. #8

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 Calibration Area

    Quote Originally Posted by IanBarber View Post
    Ted, are you scanning for a RAW output or just a regular tiff
    Always RAW, however depending on what options you actually choose there isn't much difference, but it it depends on what options you actually choose... That is actually why I like vuescan, as I understand all the options I can and I DO them myself when appropriate OUTSIDE of vuuscan. If you already have epson scan you can achieve exactly the same thing with the following exceptions, what you get with vuescan is the ability for:

    1. No need for preview (save time)
    2. Can adjust the exposure to optimum.
    3. Can easily do multiexposure (useful for old Kodachromes)

    These are are hardware related.

    You can get back to the RAW from epson scan if that is what you want?

  9. #9

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Re: Epson V800 Calibration Area

    Ted, you mentioned...

    2. Can adjust the exposure to optimum.

    Am I right in thinking that in Vuescan, you press the "Lock Exposure" checkbox which then reveals the RGB exposure slider. Moving the slider to a higher number to decrease the exposure and visa versa. Is this controlling the physical brightness of the lamp or just a software adjustment.

    Are you changing this value looking for a specific value for the film edge.

    Ian

  10. #10

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 Calibration Area

    Quote Originally Posted by IanBarber View Post
    Ted, you mentioned...

    2. Can adjust the exposure to optimum.

    Am I right in thinking that in Vuescan, you press the "Lock Exposure" checkbox which then reveals the RGB exposure slider. Moving the slider to a higher number to decrease the exposure and visa versa. Is this controlling the physical brightness of the lamp or just a software adjustment.

    Ian
    Neither, it adjusts the timing of the logic gates that clear the sensor, and gates that take charge from the sensor to the A/D to give a number. A bit like adjusting the shutter speed on a FP shutter does not speed anything up at all it just changes the delay between the curtains... The curtains always travel at the same speed.

    Quote Originally Posted by IanBarber View Post
    Are you changing this value looking for a specific value for the film edge.
    Yep to ensure that the film base is a close to "white" or about 90% in linear measurements. This also speeds up further software steps later, as I don't need to make another measurement.

Similar Threads

  1. Epson V800 - VueScan - MAC OSX Question
    By IanBarber in forum Digital Hardware
    Replies: 2
    Last Post: 24-Jan-2017, 09:25
  2. Epson V800 Scanner Capabilities
    By IanBarber in forum Digital Processing
    Replies: 11
    Last Post: 11-Dec-2016, 13:03
  3. Epson V850-Epson V800, what is the next step up.
    By Smorton in forum Digital Hardware
    Replies: 21
    Last Post: 1-Jul-2016, 10:31
  4. Epson V800 - Epson Scan Vs Silverfast
    By alanmcd in forum Digital Hardware
    Replies: 67
    Last Post: 4-Apr-2016, 09:21
  5. Epson V800 & V850. thoughts?
    By yuexiachou29 in forum Digital Hardware
    Replies: 10
    Last Post: 28-Mar-2015, 11:47

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •