My 'Cheap' Consumer Scanner Gives:3360x5184=17Mpix. Aprox 100Mb Tiff's; 10Mb low-Compression Jpg's; About 1.5Mb 'Medium' Compression Jpg's, around 0.5Mb High-Compression Jpg's.
There is a lot more detail on Halide film than most scanners, can resolve, by a LONG way. I have been messing with my Nikon and a Slide Duplicator lens and my old Printing Enlarger to see what I might pull off a 35mm; and doing it in sections.... well, I am getting down to the films halide chrystal 'grain', when I am taking 6000x4000 pixel crops of about 1/60th of the frame... ie: I blow up the neg and put the 24x16mm sensor under what would be about 4.5x3mm of negative! If you could stitch that lot together, you'd have a digital image, 48,000 x 32,000=1,500MPix! and probably around 50,000Mb disc-space in Tiff! But practically, you are getting pretty much all there is on the 36x24mm film, image wise, from between maybe 12,000x8,000 and 24,000x16,000 pixels, and tiff files, 200Mb to 500Mb 'ish'.
Trouble when people as for files of a certain Mb size... is that the IMAGE size, is umpety pixels wide by dumpety pixels tall. That defines what you have in the picture. The FILE size is only notionally related to the image size. Bigger images do tend to demand higher file-sizes, but, the file size depends on what is in the picture. If it's a 'simple' design, say a black circle on a red back-ground, then the 'data' to describe it is a lot simpler, than in the top corner is sky, with some fluffy clouds, leading into trees in the middle to left of frame, with grass fore-ground and a child playing with a yellow ball as the subject in the center, his mother in a purple dress with floral design watching from the right, as his brother in jeans and a red t-shirt comes in to tackle the boy who is wearing a Liver-pool strip.... see how many words it takes tro describe each image? That's how the file size 'works'... more complicated the pic, more digital 'words' are needed to describe it. THEN you have the influence of file format, and any inherent compression. Some file formats, take more words to describe the scene than others; be like translating my description of the two pictures into Latin, or German, or whatever. Then you have compression, and how much 'short-hand' can be applied to compress the description, like using txt spk.
So when some-one askes for a 100Mb file.... what do they ACTUALLY want, and why?
If they want a really high resolution image for reproduction work, then they possibly want as many pixels as they can get... ie 6000x4000 not 3000x2000. But its just as likely that they want an image that is 'manageable' in whatever storage and editing they use.
If I want a REALLY good base image to work on, I can 'make' 200+Mb Tiff files from my negs.... but, my scanner delivers 100Mb Tiff files straight off, and they are so big, and take up so much computer memory that I cant do an awful lot with them in a hurry, I'm sat looking at an egg-timer half the time! 10Mb Jpgs are a lot easier to work with, and take up a lot less room on my hard drive. But I need sub 1Mb high compression jpg's if I want to e-mail them to any-one.
In your situation; my line would be to ask them to be a LOT more specific as to what they actually WANT.
1/ Pixel Count
2/ Colour depth, 4-bit, 8-bit, 32-bit
3/ Format
4/ Compression
IF who you are speaking to doesn't know; tell them to go ask some-one who does and get back to you. OR you will make the original negatives available to them, or a representative (Ie; pro-lab of thier choice, at thier expense) for them to obtain the scans they require.
Keep it simple, keep it proffessional.
