Page 1 of 2 12 LastLast
Results 1 to 10 of 19

Thread: Scan Input Vs file output resolution

  1. #1
    Alan McDonald alanmcd's Avatar
    Join Date
    Jan 2016
    Location
    Sydney, Australia
    Posts
    100

    Scan Input Vs file output resolution

    At Luminous-Landscape, the ratio on page 12
    http://luminous-landscape.com/wp-con...nner-Final.pdf
    is given as: 6400ppi scan of 6x7cm negative gives a printable 58x40in
    So if all I want is to get 30x20 prints from a 4x5 negative, 1800ppi scans would provide an almost 1 for 1 ratio of input to digital file output ready for printing.
    Am I understanding this correctly?
    He is assuming a 360ppi printing. My service is asking asking for 254ppi file. I know I don't want to upsample (ie. invent pixels) but is there a problem with 'downsampling' or is there less issue with this. It doesn't have to be an exact one for one does it?

    Also: The Luminous paper talks about outputting at 16bit/channel mode. But my printer is asking for 8bit/channel. What is the effect of doing this? The file size of half but does this reduce the quality of the print ?

    Thanks
    Alan

  2. #2

    Join Date
    Nov 2015
    Location
    Melbourne, AUS
    Posts
    46

    Re: Scan Input Vs file output resolution

    Output 2 versions of the image, then do a test print print and find out exactly. Yes you will burn ink and paper but you will know exactly what you will get.

  3. #3

    Join Date
    Feb 2012
    Location
    Portland, OR
    Posts
    725

    Re: Scan Input Vs file output resolution

    There is no issue with downsampling, and in fact, depending on your workflow, it may be better to downsample. Photoshop's default downsampling algorithm produces sharpening as a side effect - in Photoshop you can choose "Bicubic" instead of "Automatic" or "Bicubic Sharper" if the added sharpening bothers you.

  4. #4

    Join Date
    Dec 2014
    Posts
    34

    Re: Scan Input Vs file output resolution

    Scan at 16bit if your image needs heavy adjustments in Photoshop. Edit the 16bit file Photoshop, save a copy as 16bit file, reduce to 8bit and save a final copy for printing.

    If you're scanning 4x5 films then 8bit is sufficient for printing in most cases.

  5. #5
    A.K.A Lucky Bloke ;-)
    Join Date
    Jan 2008
    Location
    Newton, MA, USA
    Posts
    637

    Re: Scan Input Vs file output resolution

    Alan,
    Allow me to make a couple of suggestions.

    Try to scan at closest native resolution of the scanner.
    254 x 30" = 7620
    7620 / 5" = 1524
    So the closest resolution above should be 2400 dpi, if using an Epson.

    PS is not my first choice for interpolation work. Search for "QImage" or "Perfect Resize". Both do a decent job.
    Double check the proportions. 20x30 will require some cropping in the 4x5.
    Ask the printer for the preferred profile and convert the final image to it before reducing the file to 8 bits.

    Good luck.

  6. #6
    Alan McDonald alanmcd's Avatar
    Join Date
    Jan 2016
    Location
    Sydney, Australia
    Posts
    100

    Re: Scan Input Vs file output resolution

    Quote Originally Posted by Jeff T View Post
    Scan at 16bit if your image needs heavy adjustments in Photoshop. Edit the 16bit file Photoshop, save a copy as 16bit file, reduce to 8bit and save a final copy for printing.

    If you're scanning 4x5 films then 8bit is sufficient for printing in most cases.
    Good point - thank you.
    Alan

  7. #7
    Alan McDonald alanmcd's Avatar
    Join Date
    Jan 2016
    Location
    Sydney, Australia
    Posts
    100

    Re: Scan Input Vs file output resolution

    Quote Originally Posted by onnect17 View Post
    Alan,
    Allow me to make a couple of suggestions.

    Try to scan at closest native resolution of the scanner.
    254 x 30" = 7620
    7620 / 5" = 1524
    So the closest resolution above should be 2400 dpi, if using an Epson.

    PS is not my first choice for interpolation work. Search for "QImage" or "Perfect Resize". Both do a decent job.
    Double check the proportions. 20x30 will require some cropping in the 4x5.
    Ask the printer for the preferred profile and convert the final image to it before reducing the file to 8 bits.

    Good luck.
    Thanks - I want to stick to LR which sets the profile at the same time as the 8 bit reduction in the export process. Not sure if that makes a difference but I'll keep my eye on that.
    Alan

  8. #8
    Alan McDonald alanmcd's Avatar
    Join Date
    Jan 2016
    Location
    Sydney, Australia
    Posts
    100

    Re: Scan Input Vs file output resolution

    I will say something else I do notice. And that's the need to leave the Automatic Orange Mask Expansion option ticked. It makes a difference all for the better. And the Unsharp Masking can be strengthened with good results. I can see the result of using this option before I import into LR so it doesn't force any backtracking in my workflow. All other settings I can leave as standard.
    thanks for all the help.
    Alan

  9. #9
    Alan McDonald alanmcd's Avatar
    Join Date
    Jan 2016
    Location
    Sydney, Australia
    Posts
    100

    Re: Scan Input Vs file output resolution

    Quote Originally Posted by alanmcd View Post
    At Luminous-Landscape, the ratio on page 12
    http://luminous-landscape.com/wp-con...nner-Final.pdf
    is given as: 6400ppi scan of 6x7cm negative gives a printable 58x40in
    So if all I want is to get 30x20 prints from a 4x5 negative, 1800ppi scans would provide an almost 1 for 1 ratio of input to digital file output ready for printing.
    Am I understanding this correctly?
    He is assuming a 360ppi printing. My service is asking asking for 254ppi file. I know I don't want to upsample (ie. invent pixels) but is there a problem with 'downsampling' or is there less issue with this. It doesn't have to be an exact one for one does it?

    Also: The Luminous paper talks about outputting at 16bit/channel mode. But my printer is asking for 8bit/channel. What is the effect of doing this? The file size of half but does this reduce the quality of the print ?

    Thanks
    Alan
    Let me ask another question for comment on this subject:
    If my V800 can deliver 6400ppi without breaching TIF filesize limits, this gives me an 8 x 10 ft print.
    Can someone tell me why they would then jump to a drum scan?
    It seems that drum scanning would be reserved for billboards or something. And even then, a billboard is viewed from such a long distance that this sort of resolution is totally unnecessary.
    So why do we need drum scans?
    Alan

  10. #10
    Alan McDonald alanmcd's Avatar
    Join Date
    Jan 2016
    Location
    Sydney, Australia
    Posts
    100

    Re: Scan Input Vs file output resolution

    What I am saying is that, my V800 has a non-interpolated resolution of 6400ppi.
    This means that each pixel scanned, placed on a piece of paper at the same distance apart as it was when scanned, will result in an output of 8ft x 10ft (from 4x5" negative).
    What megapixel camera would you need to do the same same thing?
    Full frame digital - 55 Megapixel?
    Am I understanding this paradigm correctly?
    Alan

Similar Threads

  1. What Input Resolution for BW Negative?
    By RedSun in forum Digital Processing
    Replies: 15
    Last Post: 14-Sep-2012, 21:38
  2. Replies: 18
    Last Post: 11-Sep-2011, 06:41
  3. Larger output size or higher resolution scan?
    By shannaford in forum Digital Processing
    Replies: 3
    Last Post: 25-Jun-2009, 15:43
  4. Film Output from Digital File
    By willwilson in forum Digital Processing
    Replies: 8
    Last Post: 15-Jul-2008, 11:09
  5. Input on video output?
    By Donald Miller in forum Digital Processing
    Replies: 5
    Last Post: 15-Nov-2007, 07:05

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
  •