If you shoot RAW it doesn't matter, you assign the color space when you export to jpeg (or other formats) for displaying on the internet, printing or whatever.

adobe98 was where we worked at NGM
sRGB was an hp microsoft set up for CRTs

https://en.m.wikipedia.org/wiki/Adobe_RGB_color_space

Yeah, this.

I shoot Raw virtually all of the time, and use Adobe Camera Raw/Photoshop for my processing.   I have my color space set to Adobe RGB in the camera but, Camera Raw ignores that, and opens the file as whatever you have set in the program.  I have Camera Raw set to to open my raw files as a ProPhoto RGB, 16 bit, 300ppi file.  After I make my initial adjustments, I then open the file in Photoshop, and continue on with my processing.  

So I do all my processing in ProPhoto RGB because it is an even larger color space, than Adobe RGB.  After all processing is complete, I can then convert the file to sRGB, or Adobe RGB, depending on the final use.  That means sRGB for the web, and since I don't do my own printing,  I simply use whatever color space the printing company tells me to use.  

If shooting jpegs, I would definitely use sRGB in the camera.

Wouldn't it matter if printing? Especially if you use an online vendor..

Yes, you should use what the vendor specifies when you export the processed RAW files.  For Costco I use the specific printer profile for the store I get them printed at.  See
https://www.drycreekphoto.com/icc/

If you are shooting jpeg then it depends on what you plan on doing with the photos.

I use Costco myself, but I can't find profiles for their canvas prints.

They don't list profiles for canvas. The generic profiles are available here
http://www.profilemyphotos.com

But you may be better off using a canvas printer who can provide print profiles. Otherwise maybe trial and error for the canvas from Costco?

In other discussions online about this others have said the canvas seems to come out darker than they intended. They have also said that they've looked at them when picking them up and have been able to reject them and not have to pay.

I did some more digging and nobody that I have seen has found who Costco is using to do the canvas prints.

I looked at other vendors and most seem to want sRGB.  I noticed that Bay Photo has a profile for soft proofing, but they want sRGB for some prints and AdobeRGB for others.

Here is Bay Photo's page.
https://support.bayphoto.com/customer/en/portal/articles/2144592-bay-photo-lab-s-icc-profile

They cost quite a bit more than Costco.  Not sure if you could print canvas smaller just to see what works (even rejecting those that look too bad) and then once you have that worked out you could go big.  They are quite a bit cheaper than other sources.

I am thinking for this you can't go wrong with sRGB.  That is what they are going to be expecting from 99% of customers.  If you wanted to use something different you would need to trial and error.

i have found that if you don't use the sRGB colorspace that everyman uses when you print at walmart, you are bound for frustration

there used to be a drycreek imaging guy that maintained a database of color profiles and target files to manage noritsu output at costcos and walmarts

hey! he is still there
https://www.drycreekphoto.com/icc/

Where to find a lab with a digital printer Our database has one of the most extensive listings available. It is far from complete, so some pointers for finding other digitally equipped labs follows.In the US, many Ritz Camera (Ritz, Kits, Wolf), Wal-Mart, Costco, and Sam's Club locations have Frontier, Noritsu, or Agfa digital printers. Other nationwide stores including Walgreens are slowly adding digital printers. In the Western US, Long's Drugs are sprouting Frontiers. Many other photo outlets also have digital printers; shop around. The quality of prints from these labs can be variable. A good initial test is if they are willing to print in non-automatic mode. If we have a profile for a lab, that's a good start.

Frederick:

• Costco #330:  10 Monocacy Blvd., Frederick, MD 21704   Phone: 301-644-1488
• Printer: Fuji Frontier LP 5900, Fuji Crystal Archive Paper.
  • Glossy paper profile, June 20, 2017
  • Lustre paper profile, June 20, 2017
• Printer: Epson 7890 Poster Printer, Fujifilm Papers.
• Photo Satin paper profile, March 30, 2016 ? Printer replaced October, 2016
• Semi-Gloss Poster Board profile, June 20, 2017

Colors inside the balloon are described using (R,G,B) coordinates. The most saturated (i.e. purest) red in any color space has an R-value of 255. Since larger color spaces have larger balloons, they contain both more air volume (i.e. more colors), and the surface of the balloon is farther from the center of the box (i.e. the colors are more saturated). Therefore, larger color spaces such as Adobe RGB contain both more colors and more highly saturated colors than smaller spaces like sRGB. A comparison of the Adobe RGB and sRGB gamuts is below. As you can see, working with Adobe RGB allows you to see and print more of most colors. Adobe RGB was designed to contain the entire color gamut available from most CMYK printers. sRGB is an HP/Microsoft defined color space that describes the colors visible on a low end monitor.

In general, you want to use color spaces that are as large as is practical. For example, if your printer is capable of producing output in a color space larger than sRGB, there is no reason to hobble your work by limiting output to the small sRGB gamut. If you do, you'll lose the saturated cyans and greens that can make your prints stand out.https://www.drycreekphoto.com/Learn/color_spaces.htm

This is true, but if the print shop cannot handle the AdobeRGB or ProPhotoRGB then it will do no good to send them files in that color space.  Thus the extensive discussion on the specific profiles.

I may just go to a local Costco and ask their photo department.

I did a fairly good sized Canvas last year for a friend of mine using a photo I took from my camera phone, and it turned off fine IMO. (She loved it)

https://www.thecanvasprintstudio.co.uk/faq/99-canvas-prints/140-colour-calibration-soft-proofing.html

both my monitor and printer support AdobeRGB so I set the camera to it. 

I've been using the A-RGB for a while now and my prints look pretty darn good. I have a older HP Photosmart D7260.