Digital projection - what size files?

Discussion in 'Digital Darkroom' started by alex_ramsay, Oct 2, 2003.

  1. I have been asked to provide some images on CD for digital
    projection. The original files, as stored on my computer, are 60
    mb TIFFs at 2000dpi from medium format originals. What size
    and resolution should I reduce them to, bearing in mind the
    need for a reasonably fast display time and a reasonably high
    quality image on screen? They will be projected to about 72"
    across. Somebody suggested they should be 1mb JPEG's, but
    the resolution has to be very low at this size.

    I should be very grateful for any advice on this subject.


    Alex Ramsay
  2. At our company we use a digital projector for all sorts of Power Point presentations. I assume, your CD will go into a PC/laptop that is hooked up to the projector. In this case you are actually limited by the screen resolution of the computer you are using (1024 x 768 in most cases), because the projector simply plugs into the video connector of the PC and sees the same signal as the monitor. So, you should be able to resample your tiffs to 1024 x 768 jpgs (or whichever screen resolution and aspect ratio will be used), which will be around 200 kb. Upon projection it doesn't look too bad at all, despite the low resolution.
  3. You are limited by the resolution of the projector, rather than the monitor; probably no higher than 1280x1024. Check your projector's specifications. Since you will not be able to display high resolution images, you should seek to show as much detail in that limited resolution by reducing the JPEG compression factor.
  4. As said, the projector's max. resolution is the limit. Actually 1-2 MB jpegs don't look at all bad when projected; it all depends on the projector and the viewing distance.
  5. I do extensive travel Photography and then have slide shows at home or for interested groups. I shoot in RAW then edit selected photos then save tham in TIFF and subsequently in excellent JPEG(size approx 2-3mb) Thereafter I insert the JPEGs one by one in powerpoint presentation in the order I want and save as slide show. Then edit presentation as custom. Thereafter I hook up my laptop to an LCD projector and advance the slides on mouse click. I find it is a bit simple & painstaking but achieve excellent results.With the HDTV LCD projector the results are awesome.
  6. Create an action in Photoshop.
    Start by going to IMAGE/MODE/8-bit then click on IMAGE/IMAGE SIZE and change the RESOLUTION to 96ppi (this the same resolution as a MAC screen, PCs are 72ppi) make sure you've unticked the resample image box and click okay.
    Then go to FILE/AUTOMATE/FIT IMAGE and set the width and height to those of your projector (usually this 1024 x 768 pixels) and click okay.
    Next go to EDIT/CONVERT PROFILE. In the destination box select sRGB. There will be some numbers after this, but don't worry about them.
    Now do your sharpening. If you ask 10 different photographers they'll give you ten different answers about sharpening. Personally, I sharpen 2-3 times for slideshows using UNSHARP MASK, I'll set AMOUNT -125, RADIUS -0.2, THRESHOLD -0.
    Save as JPEG QUALITY 11 in a folder of your choice, call it SLIDESHOW IMAGES or something. Don't forget when you close the original TIFF not to save changes.
    Finish recording action.
  7. I just bought an Epson EX 5210 digiatl projector, about 400 dollars, . I'm a painter and wanted to project sketches that I took with my iphone camera. I downloaded on my mac onto a USb card and plugged it onto the projector. But in a few days I sent the thing back because i was having so many problems with the projector either choosing tp show some images, or not show some images and I could not figure out what i was doing wrong. I tried in both large and small DPI, used RGB, saved as both jpeg and tried PNG, and it was just hit or miss. If I get another projector will it do the same thing? Any one have any ideas? I'm ot very techy.

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