My scanner tends to "enhance" making the results a bit more vibrant with more contrast. It doesn't pick up subtle changes in color variation nor does it do a great job picking up certain blues and yellows. The scanner also does poorly with natural colors of paper like Arches versus bright white papers often appearing blotchy.
I never felt comfortable using a camera for my artwork because of white balance/color cast due to lighting but at least the camera lens picks up what the scanner does not.
In either case, I'm always having to try and fine tune in Photoshop Elements attempting to match actual tones and colors that I see in my journals. The worst fine tuning when dealing with photographs being the need to remove the color cast or where part of an image might be brighter than another area.
Using Camera:
For the photographs, I used my Samsung Note 8 camera. The first two photos were taken within a thirty minute to an hour time frame so not much change in lighting from the window I was sitting at. By the third photograph, the lighting was definitely different creating a bluish color cast I definitely had to try and fix. In doing so, I lost part of the pencil line work of the plastic shelf unit the plant sits on. All three I had to lighten a bit. I really do not enjoy dealing with white balance issues. Maybe if I understood it better and how to avoid in the first place, it wouldn't be so bad.
Although working to remove color cast, the first two still have a yellowish to gray tone whereas the final photograph still shows a slight blue in the white of the paper. At least the green colors picked up by the camera lens are closer to the actual colors and variations in the watercolor sketch.
Using the Scanner:
I scanned twice making adjustments in the scanner's software. Neither could pick up the green variations the camera lens on my phone picked up.
Left: Auto correction in software at 24 Bit and 300 resolution
Right: Turned off Auto setting and changed to 48 Bit and 300 resolution
What the difference is between 24 and 48 in how it affects colors, etc. is beyond me. Something I'll have to do some research on.
In comparison, turning off the auto correction picked up more of the blues that actual leaves have however still did not render correctly all the green variations in the sketch. Both scans picked up more of the green making the results more lively than in the photographs.
The actual colors and tones on the page in my journal would fall somewhere between the final photograph above and the right scan below.......leaning more towards the photograph.
My final thoughts:
I still prefer to scan since I often use my art images for making magnets, note cards, and other craft projects. Scans are cleaner for printing. Normally the only adjustment I have to make in Photoshop Elements is in the brightness/contrast controls. The lighting with scanning is constant. Just wish the scanner picked up the subtle variations in color that a camera lens can pick up. For printing, I wouldn't want the texture of the paper to show.
As for the photographs.............even if I used my good DSLR, it makes no difference when dealing with white balance. It might if I knew how to properly set the camera for different lighting situations that constantly change or had a better artificial lighting setup when taking photos of my artwork. I do like that the camera can pick up the color variations the scanner does not plus it's ability to pick up the texture of the paper for times I might wish for it to show.......whereas the scanner does not.