This is probably the closest place, yes, given the technology at play here. It is very much in the realm of photography and digital imagining in general.
Before I start, realize I say all of this having experience in the print publishing industry, having served as both a newspaper designer, as well as having created corporate print piece for 3 of the past 5 years. And then I've been an active photojournalist for more than a decade now. My use of scanners is going on 20 years now (not quite, but getting closer). So....
Scan resolution - 300 dpi vs 600 dpi
Pretty much all current model scanners (and even some past ones from recent years) have the ability to scan those documents so finely that it can pick up the flaws of the original printing process. In other words, it can scan the image, plus pick up non-image visual elements!
If this is for archival use -- a file just to keep for whatever backup purposes -- I would make a scan at 600dpi.
However, 600dpi is a huge pain in the butt to work with, as it creates large files that lag on the CPU and RAM. And the output won't necessarily benefit from that size anyway. It's a good archive file, but that's really it. For actual working use, a 300dpi downsized version is what I'd work with. A 300dpi scan is just as good. At 600dpi, you're picking up a lot of print noise, not just image. At 300dpi, you're mostly just getting the image. Depending on the print quality of the scanned ticket, you may have to run some third-party de-noise filters on it (NeatImage), or maybe just run a Photoshop-native despeckle filter.
A lot of flatbed scanners are tuned for 300dpi scanning. All other resolutions tend to look crappy. Many so-called 600dpi flatbed scanners can't actually optically resolve 600dpi worth of details. Anything above 600dpi -- be it 1200dpi, 2400dpi, 4800dpi, 9600dpi -- is generally interpolated (fake!). Only dedicated film/slide scanners tend to truly scan at something as high as 4800-9600dpi, in the pro range. (My pro Nikon Coolscan V, for example, is 4800dpi true optical scanning, as it's equipped with Nikon ED glass optics.)
My advice to you is to use 300dpi.
The only exception
would be if your going to significantly enlarge the piece when it's printed. For example, a small ticket stub that is 3 inches across being printed 200% at 6 inches across. For that, I'd definitely go with 600dpi. Note that the TV size does not matter. DVD-Video format can only use a max size of 720x480. Even HD/Blu-ray is limited to 1920x1080 resolution. I don't refer to the television when I mention physical size -- only print.
Colorspace - sRGB vs Adobe RGB
Colorspace is mostly determined by your choice of workflow calibration, from scanner to monitor to printer. I work within the sRGB system. Digital photos off my pro Nikon DSLRs (D3, D200, etc) are all set to sRGB colorspace, as my work is always dual-processed for both web and print use, as well as video use.
The only time I'd shoot AdobeRGB (aRGB) is if I were doing art/landscape photography, with the intention of selling large prints, and using a very exact/controlled print process -- which is never, because I'm a sports photographer! My prints look great in magazines and newsprint, using sRGB. Many of them are shot JPEG, too -- quicker to process if you skip RAW. That's standard in news.
Adobe RGB offers a wider gamut, but your already-processed ticket scans long ago lost whatever gamut that might be. Many would argue that the gamut really only applies to extreme colors anyway, or to large-palette gradients (sunsets/sunrises). For novice users, AdobeRGB is more of a hindrance than anything else. Any incorrect use along the way and you'll end up with a wimpy-colored image with contrast problems. Most monitors are unable to truly display AdobeRGB anyway.
sRGB is also the native calibration for most equipment, especially consumer gear.
sRGB vs AdobeRGB is an old photographer argument. Not quite as old as Nikon vs Canon, but well into the decade category.
Then again, if I want to take my printing seriously, I'll be converting to CMYK anyway, and using Pantone color selections for non-image specs, so most of the RGB arguments become null and void. Printing RGB is mostly for photos and amateurs. All printers use a CMYK print process, so even if you give it an RGB spec, it's going to get converted. Many modern press setups can do this at the point of print, but in years past, we had to set the projects up as CMYK before submission.
That's another reason your scanned tickets don't need high-accuracy wide-gamut scanning -- whatever once may have been there is now long gone.
My advice to you is to use sRGB.
Bit depth - 24 bit vs 48 bit
I almost don't want to get into the full explanation of this one, as it involves a lot of color theory. And beyond that, it doesn't really matter.
When it comes to optical flatbed scanners, especially consumer models (and even lower-end pro models), the specs are cooked. Sure, the scanner can create a file in the 48-bit colorspace, but that actual image data is generally still closer to 24-bit (8 bits per color). The numbers are there to simply help sell more scanners.
Bigger numbers look better to clueless buyers. It's a concept photographer Ken Rockwell refers to as "measurebating". Companies and people love to brag about how many megapixels, DPIs, bit depths, etc, their product has. But most times, neither the seller nor the user seems to truly understand what it means, and how it's important (if it's important). There's an odd disconnect between engineers and marketers at companies, too, where a product is created with certain features, but the marketing departments so excessively embellish the importance that it's a almost a lie.
Just trust that your scanners can't really scan much better than 24 bits, and use it. Those 48-bit files are large, and difficult to work with. Few programs can open 48-bit files, so you'd have issues.
My advice to you is to use 24-bit color depth.
I would say that my advice is general advice for you, and is valid on all items that you wish to scan. The postcards might benefit from 600dpi scans, but it really depends on their quality. It would have to be a high-gloss photograph to benefit from 600dpi. But again, the files may be hard to work with at that resolution. Whether your scanner is good at 600dpi is another issue.
HP scanners suck.
I'm just going to leave it at that. While they surely operate as a scanner, the quality is inferior to Microtek and Epson scanners.
I've used that exact Epson scanner, the Epson Perfection 4490
, and it was fine. When it comes to scanner advice, I always suggest the current Epson line of scanners. They even surpass the quality of one-time leader Microtek in scanning speed and quality. The Epson Perfection V300
and Epson Perfection V600
(300 with ICE) are my top suggestions.
My advice is to use the Epson.
Judging from your comments in the questions, I think you knew some or most of this, and just need reinforcement. I think you're on the right path.