A few questions about photo store processing

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Even though they use computers Its 100% percent photographic chemistry correct?

Is it possible to make effects on these processors? I know I can make an image a solid color, like cyan, or green. Much like a color copier? Anything else?

Is it possible to print on a transparency rolls from processors?

How much do slide positives usually cost? Are they still making them?

How much is resizing positives usually cost?