OK, I understand the compression scemes, But Why when I load the 2.8 meg jpeg in PS, and work it and save to tiff it becomes 20-30 meg? I am not adding information? I am just saving to a different file type? A friend wanted to know how I ended up with a 30 meg file from a 6.8 meg camera..Just curious. Harry
This is because when jpeg image is loaded to photoshop it is decompressed and usually uses 24 bit color format as any other "true color" image format. Memory consumption is roughly width*height*3 (24 bit image = 3 bytes per pixel). Example: Jpeg Image with dimensions 1024*768 gives you 2.35 MB of memory used. File size might be just 300kb. When saving image to TIFF it stores this uncompressed image data in memory to target file (sometimes without compression used).
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