manis Posted October 23, 2008 Report Posted October 23, 2008 HII am making a slideshow that will be shown on a beamer that I don't know. As it will be shown for a big audience, I suppose it will be a quality beamer. The only request from the organizer is that the resolution of the pictures shouldn't be bigger than 1920x1200. As I am working with a slr I put my pictures on a resolution of 1800x1200. But I also put my pictures on dpi 300. Will this give a problem or is it better to keep the 1800x1200 and put the dpi on 72? I don't know which computer they are using .ThanksReine Quote
JPD Posted October 23, 2008 Report Posted October 23, 2008 But I also put my pictures on dpi 300. Will this give a problem or is it better to keep the 1800x1200 and put the dpi on 72?The number of DPI doesn't change anything on a screen, it's only when we print. Quote
xahu34 Posted October 23, 2008 Report Posted October 23, 2008 Hello Reine,You may have a look here!Best regards,XaverMunich Quote
xahu34 Posted October 23, 2008 Report Posted October 23, 2008 ... will be shown on a beamer ...By the way, the word "beamer" seems to be used only in the Dutch and in the German language areas.Regards,Xaver Quote
davegee Posted October 23, 2008 Report Posted October 23, 2008 Reine,Check again.Should that be 1920x1080 (not 1200)?The inference is that their projector is 1920x1080 - I don't think there is a 1920x1200 projector?DaveG Quote
Guest Yachtsman1 Posted October 23, 2008 Report Posted October 23, 2008 In my experience, pictures saved at 300dpi suffer from moire (shimmering) when animated, I usually use 150dpi or less at 1024x768.Yachtsman1PS I assume beamer is slang for projector Quote
fh1805 Posted October 23, 2008 Report Posted October 23, 2008 Eric (Yachtsman1),The dpi (which stands for dots per inch) has no effect whatsoever on the quality of a projected image or on the size of the image file. Dpi has meaning and function only for images that are being digitally printed. If you doubt me, look at the three attached images. They are all 1200 pixels wide and 1600 pixels high and saved at quality level 5 (medium) as jpgs. The only difference was in the dpi setting during the "resize" operation. There is no difference between them.regards,Peter Quote
fh1805 Posted October 23, 2008 Report Posted October 23, 2008 Eric,Sorry, should have added that moire shimmering is a function of what is in the image and not of the size or anything else. It comes about because of the particular subject matter and the animation (in terms of pan or zoom or rotate) applied to it.It's appearance can be combated by using the Blur option within PTE v5 O&A or the Mip-mapping option in v5.6 beta. This applies to the whole image. An alternative approach is to apply 1% Gaussian blur via Photoshop to just those parts of the image where the effect is being seen.regards,Peter Quote
Gilio Posted October 23, 2008 Report Posted October 23, 2008 Hi Reine, welke projector wordt er gebruikt tijdens de projectie, waarschijnlijk JVC dan is 1400 pixels genoeg wat men altijd gebruikt! dpi is niet van belang!Giel Rombout. Quote
JPD Posted October 23, 2008 Report Posted October 23, 2008 In my experience, pictures saved at 300dpi suffer from moire (shimmering) when animated, I usually use 150dpi or less at 1024x768.Yachtsman1How it's possible? I never see any difference on a screen, even from moire. We probably haven't the same experience. Please, be enough curious to save a file at 300 dpi and at 72 dpi, and compare them with a tool, you will see no byte are different, there will be exactly the same. Quote
manis Posted October 23, 2008 Author Report Posted October 23, 2008 Well,This is quite a bunch of quick and clear answers!I don't know what projector is being used though...I'll leave my pictures as they are...even if there are too big, I don't think this will cause any problem.Thanks a lot Quote
Guest Yachtsman1 Posted October 23, 2008 Report Posted October 23, 2008 Eric,Sorry, should have added that moire shimmering is a function of what is in the image and not of the size or anything else. It comes about because of the particular subject matter and the animation (in terms of pan or zoom or rotate) applied to it.It's appearance can be combated by using the Blur option within PTE v5 O&A or the Mip-mapping option in v5.6 beta. This applies to the whole image. An alternative approach is to apply 1% Gaussian blur via Photoshop to just those parts of the image where the effect is being seen.regards,PeterHi PeterWhen I first started using PTE I saved my images at 300dpi, and experienced moire in some instances, when panning over water and brickwork etc. I tried reducing to 150 dpi and the moire reduced to the extent that it was acceptable, hence the statement, similar to images over 1mb.???Yachtsman1 Quote
mbskels Posted October 24, 2008 Report Posted October 24, 2008 Hi PeterWhen I first started using PTE I saved my images at 300dpi, and experienced moire in some instances, when panning over water and brickwork etc. I tried reducing to 150 dpi and the moire reduced to the extent that it was acceptable, hence the statement, similar to images over 1mb.???Yachtsman1My understanding is that the dpi (ppi) setting is contained within the metadata section of an image file in a similar way to aperture, shutter speed, date etc. The image data would be unaffected by any change in dpi (ppi) setting.If your observation is correct then it would have significant implications. Perhaps someone with a more detailed knowledge of how animations are created at the code level could comment.Malcolm Quote
xahu34 Posted October 24, 2008 Report Posted October 24, 2008 My understanding is that the dpi (ppi) setting is contained within the metadata section of an image file in a similar way to aperture, shutter speed, date etc. The image data would be unaffected by any change in dpi (ppi) setting...Malcolm,Your understanding is correct! See also here.Best regards,XaverMunich Quote
fh1805 Posted October 24, 2008 Report Posted October 24, 2008 Eric,..When I first started using PTE I saved my images at 300dpi, and experienced moire in some instances, when panning over water and brickwork etc. I tried reducing to 150 dpi and the moire reduced to the extent that it was acceptable...Could you post an example of a 300dpi and 150dpi image that you have actually used? I find it hard to believe that simply changing the dpi value could have any effect at all on shimmering. As Malcolm has indicated, the dpi value is simply meta-data associated with the image file and has no direct bearing on the data content of the image file.regards,Peter Quote
xahu34 Posted October 24, 2008 Report Posted October 24, 2008 Just an additional remark:You can make copies of your images and apply the free stripper application (http://www.steelbytes.com/?mid=30), and remove the exif data, leaving the image data unchanged. These copies will not possess any dpi values. Your projector will not care for this fact.Regards,XaverMunich Quote
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