Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 30

Thread: Epson V800 Calibration Area

  1. #11

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Re: Epson V800 Calibration Area

    Quote Originally Posted by Ted Baker View Post
    Neither, it adjusts the timin of the logic gates that clear the sensor, and gates that take charge from the sensor to A/D to give a number.
    So briefly how are you using it your workflow and was i correct about pressing the Lock Exposure to reveal the slider

  2. #12

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Re: Epson V800 Calibration Area

    Once you have your scanned RAW file in Tiff format, are you then doing the conversion in ColorPerfect, Negfix8 or another way

  3. #13

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 Calibration Area

    Quote Originally Posted by IanBarber View Post
    So briefly how are you using it your workflow and was i correct about pressing the Lock Exposure to reveal the slider
    Yes, removing the lock exposure reveals the slider, and then you can manually control the exposure. If you don't do that it will use the value calculated from the last preview scan. This is downside of vuescan is that while you CAN choose exactly what you want if you choose the wrong option, you might not get what you wanted...

    How I use it?

    I have all the options set I want for a particular type of film. I scan the entire platen area in one pass.

    These options are:

    1. RAW, i.e. take the digital values that come out of the buffer after the A/D has converted them and pixel shift algorithm has completed, and put them in a file untouched.
    2. Have the exposure set so that the RGB values come close to 90% linear values (can see on the raw graph) for a particular film stock. For BW you only need one color...

    Nothing else. Very simple and fast, or at least as fast as epson is !

    I then use software details here https://www.largeformatphotography.i...-film-scanning

    though I use a more updated version.

    1. To digital cut and frame each image
    2. I then invert using the same (at least similar) method as the Kodak Cineon system, though I am still building my calibration matrices... (that is not in the github release)

    I have something similar working for my D700 (DSLR).

    Ultimately I hope to make something useful that will probably work best with A DSLR, but my old 4990 is still useful. Plus I like to some photography at the same time :-)

  4. #14

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Re: Epson V800 Calibration Area

    Thanks Ted.

    Just to clarify one thing...
    You mentioned that you adjust the exposure slider to give you white or 90% of the film edge. Would the film edge not give you black as it is clear or am I missing some step

  5. #15

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 Calibration Area

    Quote Originally Posted by IanBarber View Post
    Thanks Ted.

    Just to clarify one thing...
    You mentioned that you adjust the exposure slider to give you white or 90% of the film edge. Would the film edge not give you black as it is clear or am I missing some step
    No the film base being the most transparent part of the image will let the most light through, this will give the highest value on the sensor. i.e. close to "white" or "1" if your using normalised numbers. I would expect to see normalised values approximately 0.9 in the file i.e. 0.9 x 2^16 = 58982. If you put the Raw graph on it vuescan it will show a graph of these values against a linear scale. That is good enough, it just the consistency that matters 0.85, is just as good a 0.95. But you do not want to go over 1.

  6. #16

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Re: Epson V800 Calibration Area

    I have just done a preview of some film edge. Would you agree this doesn't look right. The graph is also set to RAW view

    Click image for larger version. 

Name:	Screenshot 2019-08-15 at 17.49.37.jpg 
Views:	14 
Size:	36.8 KB 
ID:	194368

  7. #17

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 Calibration Area

    Quote Originally Posted by IanBarber View Post
    I have just done a preview of some film edge. Would you agree this doesn't look right. The graph is also set to RAW view

    Click image for larger version. 

Name:	Screenshot 2019-08-15 at 17.49.37.jpg 
Views:	14 
Size:	36.8 KB 
ID:	194368
    No it looks good, if you look at the raw file outputted it should look white or have values close to white, it might vary a bit depending on what program you open it with.

    If you scan RAW it should look like film, if may look dark at first if you imaging tool does not understand that file is saved with a gamma of 1. i.e. without any gamma encoding. If your shooting HP5 it should look like a negative.

    If you tick the lock exposure butting what factor is displayed?

  8. #18

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Re: Epson V800 Calibration Area

    The outputted value of the film edge in Photoshop shows an L value of 97

    I presume by scanning the entire bed, you then manually crop the image. Doe scanning the entire bed not affect the final image size?

  9. #19

    Join Date
    May 2017
    Posts
    232

    Re: Epson V800 Calibration Area

    Quote Originally Posted by IanBarber View Post
    The outputted value of the film edge in Photoshop shows an L value of 97
    Using L in photoshop in THIS instance will probably just confuse you if you don't understand the underlying formula.

    Quote Originally Posted by IanBarber View Post
    I presume by scanning the entire bed, you then manually crop the image.
    No I as mentioned earlier I wrote some software to do that, but for 4x5 it is not really necessary

    Quote Originally Posted by IanBarber View Post
    Does scanning the entire bed not affect the final image size?
    Yes, until it is cropped, but that doesn't really matter.

  10. #20

    Join Date
    Oct 2013
    Location
    Doncaster UK
    Posts
    560

    Re: Epson V800 Calibration Area

    Quote Originally Posted by Ted Baker View Post
    Using L in photoshop in THIS instance will probably just confuse you if you don't understand the underlying formula.
    Is there a method you can suggest to measure the value of the white or is an understanding of the formula required for this

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
  •