scanning pictures

[raffage75]

hi guys

i was wondering which resolution you should use te scan magazine pics so you can use them for your vjing? i have lots of mags with great foto's but haven't got a clue about resolutionstuff...

[LEVLHED]

I'd scan at as high a rez as you can for archival purposes, then cut them down in a editing app (photoshop or whatever) to bring into your VJ app...you'll have to just experiment a bit to figure out whats the best balance btwn file size/rez for live use...

[eXhale]

If you are using svideo/composite cables for the projection, anything higher than the video resolution will not be seen (with NTSC it's 800x600 pixels I think, and PAL is a bit lower). Using high-resolution pictures with several millions of pixels will just waste the precious resources of your computer.

[many2]

When working with still pictures a good thing to remember is that you can ANIMATE them and that most of the time this extra resolution you'll have will be very useful. If the image isn't moving (rotations, zoom in picture, etc.) then there is no point in having your sources in higher rez, but it is still a good idea to scan your image at medium resolution and scale them down in photoshop.

Also remember that DPI is for print only and that this concept has absolutely NO use at all for video. When defining the DPI for your scan you are telling your computer how many points (pixels) you want to be computed on a given inch line. So if you have a 5x7 photo and you scan it at 100 DPI, this will give you a 700x500 image. Scanning at twice the needed resolution is a good idea : it will eliminate some scan artefacts by resampling the image when scaling down to the desired resoltuion.

Hope this helps.

Many-2

[raffage75]

thx for the input guys! It's exactly for animation that i want to use them. so if i understand correctly: for a 800x600 pixel monitor you should scan a 8x6 image at 200 dpi, and then the resolution should be fine, even if you wanna animate the image?

[many2]

raffage75 wrote : >>for a 800x600 pixel monitor you should scan a 8x6 image at 200 dpi, and then the resolution should be fine, even if you wanna animate the image?<<

an 8x6 image scanned at 200 dpi will give you a 1600x1200 image. This will give you the opportunity to zoom in at 2x and still keep a 1:1 pixel ratio between your source and your output. If you want to be able to zoom even more you should scan with a higher DPI ratio. Remember though that at higher DPI ratios you may actually scan at a higher resolution than the print you are scanning (particularly if you are scanning from a printed source instead of an actual photo) : you will see the dots of the print. This can be a good effect if you like this style but the point is there is a limit to the resolution you can use and this limit can be either your hardware (scanner) capabilities or your source's resolution, whichever is lower.

Working with source images at 2 times the resolution of the output you are producing can be very useful too for rotation, distortion effects and the like. This is a process called supersampling and will keep a better image quality when you distort your source since it can feed the software some information about the pixels between two pixels in the output. This means that for a given pixel in your output a given number of pixels (4 pixels for a 2:1 ratio between source and output resolutions) will contribute their color information to produce the resulting image. This approximation process will give you smoother movement and should prevent some aliasing artefacts.