SitePoint Sponsor

User Tag List

Results 1 to 6 of 6
  1. #1
    SitePoint Enthusiast davidorsini's Avatar
    Join Date
    Nov 2006
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Lightbulb resize image and set quality (dpi)

    I have found the ImageResize() and ImageScaleToFit() commands for coldfsuion to set height and width values for an image file. Is there any way to modify the DPI of an image? I need it so my clients can upload an image and we modify/control the height, width, and dpi as we will be using these image files for both email and print correspondences.
    David Orsini
    Atlanta, GA
    Georgia Tech

  2. #2
    SitePoint Addict
    Join Date
    Dec 2008
    Location
    Aberdeen, Scotland
    Posts
    379
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    DPI doesn't matter for the email it's the file size that counts.

    Can you not upload an 300+ DPI photo for your print job, make another copy and resize for email? Compare the file sizes after that but it should be ok.

  3. #3
    SitePoint Enthusiast davidorsini's Avatar
    Join Date
    Nov 2006
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I am not going to be uploading anything. My clients are the ones uploading the photos. So I need a mechanism to ensure the file uploaded meets our size and quality (dpi) requirements.
    David Orsini
    Atlanta, GA
    Georgia Tech

  4. #4
    SitePoint Addict
    Join Date
    Dec 2008
    Location
    Aberdeen, Scotland
    Posts
    379
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Is there any way to modify the DPI of an image?
    Not that I'm aware of.

    But my suggestion is - Your client uploads the print quality image to the site. ColdFusion takes a copy of that file and resizes and saves this in a separate location for your email usage.

    As I say as long as the file resize (and quality) is suitable for emailing then why does the dpi matter?

  5. #5
    Community Advisor silver trophy

    Join Date
    Nov 2006
    Location
    UK
    Posts
    2,559
    Mentioned
    40 Post(s)
    Tagged
    1 Thread(s)
    Hi Clarkee/Davidorsini

    The only measure that really matters is the pixel dimensions.

    e.g a business card at a size of 89mm x 51mm needs to be printed at a minimum of 300dpi for good quality = 1051 x 602px

    As long as the pixel resolution is sufficient then all good.

    The dpi can be important for non-technical end user when printing stuff out :

    If I take my 300dpi 89mm x 51mm 1051 x 602px image and print it out in typical software, it will appear at the correct size.

    However, if that image was saved at 72dpi (default for many dynamically created images) when opened in a typical application it will print out at 37cm x 21cm, and will appear pixelated at that size. The resolution of the information stored in the image is no different, just interpreted differently.

    The dpi is just really metadata on how big each pixel gets printed. In jpeg files it can be programmatically changed without resizing or processing the image by altering a few bytes in the files header.

  6. #6
    SitePoint Enthusiast davidorsini's Avatar
    Join Date
    Nov 2006
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    My clients currently just email the picture to us and we manually resize everything in Photoshop. It looks like that will have to be my best bet for the time being. I tried using the 72dpi image for printed pieces and it doesn't look nearly as good. We are printing peoples' pictures so it has to be really high resolution to print out well.
    David Orsini
    Atlanta, GA
    Georgia Tech


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
  •