GIMP + LENSPIRATION + Mr. Quebec = Problem

Home Forums Photography Q&A GIMP + LENSPIRATION + Mr. Quebec = Problem

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  • #8192
    Mr. Quebec
    Participant

    I can’t drop pictures edited with GIMP on Lenspiration. I’m learning to play with GIMP (thanks to buddingphotographer 🙂 ), but I didn’t found out how to attach pictures on Lenspiration. When I attached a picture edited with GIMP, it said :”Sorry, this file type is not permitted for security reasons.”
    Any help will be greatly appreciated!
    P.S. The picture I tried was first edited with Windows Live Gallery, than with GIMP.

    #8193
    Ezra Morley
    Moderator

    Let me guess. You saved the image from GIMP which resulted in a file which ended in ‘.xcf’ right?

    I’m so sorry about that, I should have thought to tell in my tutorial how to export to .jpg! You must hit “Ctrl + E” and make sure to export the picture as “Picture.jpg” file instead of “Picture.xcf”

    #8207
    James Staddon
    Keymaster

    Good to know @buddingphotographer! That’s something I wouldn’t have known. Let us know, @Mr. Quebec if it works!

    #8211
    Ezra Morley
    Moderator

    A little more clarification…

    From Wikipedia:

    XCF, short for eXperimental Computing Facility, is the native image format of the GIMP image-editing program. It saves all of the data the program handles related to the image, including among others each layer, the current selection, channels, transparency, paths and guides.

    It is roughly equivalent to Photoshop’s .psd file. GIMP is basically the only software that can open .xcf files, so it’s not a good file format to use when sharing files with others. For sharing your pictures, you have to use a file format that anyone can open. The most common is JPEG (or JPG)

    You have to “export” from GIMP to .jpg to get a file that you can send to anyone. When it brings up the dialog asking what quality to save as, you can often select a value of around 90 if you just plan on saving for the web, i.e. for Lenspiration. If you plan on saving it for long-term storage, you should save it in the highest quality possible. (100)

    #8219
    Mr. Quebec
    Participant

    Thank you again, buddingphotographer!
    I successfully exported a GIMP edited picture on jpeg on my computer, and now I’ll see if it works on Lenspiration.

    When it brings up the dialog asking what quality to save as, you can often select a value of around 90 if you just plan on saving for the web, i.e. for Lenspiration.

    Well, I had to bring my picture way below 90 to get almost 2 Mo (which is around the maximum file size for Lenspiration.) maybe around 60 or 70, if I can recall correctly. Is it normal?

    • This reply was modified 50 years, 7 months ago by .
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    #8460
    Ezra Morley
    Moderator

    The lower you bring down that number, the lower the quality of the picture. Here’s an illustration…

    Jpeg Quality Comparison

    Here’s one made with an actual photograph, taken from this thread.

    Jpeg Quality Comparison

    You need to view it at 100% to really see differences correctly, here’s a link to view it fullscreen

    Obviously the “Quality 0” is an extreme example, but it shows the kind of processing that’s going on. Take a look at the background color as the quality decreases, it changes from an off-white to light pink, to light green, to grey, to white.

    Also of interest are the file sizes…

    Jpeg Quality Comparison - File Size

    Attachments:
    #8538
    James Staddon
    Keymaster

    These are some awesome comparisons, @buddingphotographer! Very helpful.

    So, to help @Mr.Quebec get a smaller file size, is there a way for him to reduce the actual pixel dimensions? His most recent upload is 4272px wide. This is why it’s difficult to get it below 2MB. Uploads really only need to be 800px wide, or 1600px wide if he wants to display full screen.

    The Quality settings you have been discussing thus far does effect file size, but only slightly. Reduce the pixel dimensions and you’ll be on the road to solving this problem.

    #8556
    Ezra Morley
    Moderator

    Yes, 4272 pixels is definitely too large. You will have to compress it so much to get it down to the 2MB limit that the compression becomes painfully obvious. 🙁 I think it’s way better to reduce the pixels to ~2000 pixels, and combine that with some compression to get the file size well below 2Mb. Most of the pictures I post on this forum are from 500 – 800 KB, which is less than half of 2 MB!

    I found a really good tool for visualizing the file size difference just from compression with Lightroom! Jeffrey’s “JPEG Export Quality Tester” Lightroom Plugin It’s a plugin for Lightroom that will export one picture at various compression levels with the same pixel dimensions. I was truly astounded by the results! I have always exported my pictures from Lightroom at 100% Quality; I mean, after all, photographers need the best quality, right? However, after seeing the results with several different pictures exported with the plugin, and comparing them at 1:1 zoom, I concluded that there’s absolutely no point in a jpg that “weighs” 8 MB instead of 3 MB when there’s no visual difference! If I ever need the high-quality files, I can always re-export a high quality jpg from the original RAW file.

    What I recommend for @Mr-Quebec is to use Fast Image Resizer, it will reduce pixel dimensions and compress at the same time. The default of 88 for the compression is fine, that’s what I’ve always used. Open the ‘Resolution’ dropdown on the little Fast Image Resizer window, and click on ‘Edit List’ then type ” 2000×2000 ” click ‘Add’ then choose that option when resizing to post on Lenspiration. It’s that simple!

    #8568
    Mr. Quebec
    Participant

    Thanks, buddingphotographer!

    #8574
    James Staddon
    Keymaster

    Say, @buddingphotographer, what quality setting number while exporting from Lightroom did you find gave you the smallest image size while still retaining a high visual quality?

    #8637
    Ezra Morley
    Moderator

    It really depends on the photo. A photo with large areas of one color, (lot’s of blue sky for example), will need a higher quality setting, because the gradients will quickly degrade to large blocky areas.

    See the attached screenshot: The file-names (highlighted) show the quality settings used. You may need to view your screen at an angle to see the “chunky” sky on the left, the right is high enough quality that the gradient is pretty much smooth, and there aren’t many visible artifacts.

    I think as a general rule of thumb, you can get by with a setting of 77 for Lightroom. It will probably halve the file-size, while to the casual observer at normal screen resolution, there is no discernible difference! Naturally, if you’re exporting for backup, or for prints, you’ll want high quality.

    (GIMP uses a different jpeg algorithm, so the settings don’t necessarily carry over, I personally wouldn’t go below 75 with GIMP either. If the file size still isn’t small enough, you should reduce the resolution, instead of quality settings.) I’ve found that when you’re working on a project in GIMP, and you export a jpeg preview, you can set the quality to 95, only 5 less than High Quality, and it more than halves the file-size! See the illustration from my recent project below. (As you can see, I made quite a few revisions!) The two files that are circled were exported at 95 and 100 respectively! That is very useful when you’re just exporting a quick preview to show the current progress on a project.

    Attachments:
    #8656
    James Staddon
    Keymaster

    Very helpful, @buddingphotographer! It’s nice to have a “rule of thumb” to start a process from. 77. Good to know!

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