How can I take color accurate images with a white background in a light tent?

Question

I want to take pictures of hundreds of Lego pieces with a white background. As a beginner in photography, I am using the first DSLR camera that I could get my hands on and I bought a light tent for proper lighting and a clean background.

^{Left: Exposure time: 1/6 – BG is white but torso appears too bright, Right: Exposure time: 1/13}

Initially, I used a long exposure time to get a white background. The torso appears too bright, shown in the image on the left. Therefore I adjusted the shutter speed to get the image on the right.

^{Left: How I used the "curves" tool in my editing app ("Photos" on macOS), Right: Edited image (the right one from above using 1/13)}

Then I edited the image such that the background appears white again. I used the "curves" tool and I think the result does not look too bad. Also, the colors on the torso appear more accurate.

But it feels a bit weird and complicated to do it that way. How should I go about it and should I make some changes regarding lighting, camera settings or post-processing?

Bonus Question: How can I make a white object stand out?

^{Left: In my image the white object blends into the background, Right: An example of how it should look like. source}

Some of the parts are white. When I take an image, the object blends into the background. I want to get a result similar to the image on the right (not mine). What can I adjust to get it right?

Camera / Lighting Settings

^{Left: Settings used for my images, Right: Foldio Smart Dome used for lighting/background.}

With the Foldio Smart Dome I think I cannot light the subject and the background separately and the light is diffuse. I keep reading that it makes sense to light the subject and the background separately and I wonder whether my equipment is not ideal.

Side Notes: I bought this particular Smart Dome because later on I want to take 360 degree images. And I am shooting in RAW.

Answer 1

Fun topic- you're going to learn a lot as you practice with this. First and foremost you need to 'lock' your color temperature. You can easily do this by taking a grey card and placing it inside the light source area and photographing it. Then use that as a 'custom' white balance. That should compensate for any oddities in the spectral source for the light- can't tell if it's FL or LED ().

LED light sources will also (depending on the quality of the LED light) mess with the color fidelity of your objects. The 'blues' may be enhanced beyond what they look like, and the reds may be subdued because the light itself is lacking in these spectral responses. In order to fix this issue, you need a color calibration target swatch- usually a card that you take photos of at different exposures, run software on it, then get a good calibration matrix. This shifts the response colors in your image to better match what they should have looked like.

After you've fixed the color and density/brightness, then you're on to setting your objects up. You've already discovered that overexposing doesn't make a white object 'pop' off of the edge. Now you're into techniques of shooting in light tents and it can get complicated- but the good news is you're able to do it cheaply because it's digital, not film.

Some google/youtube tutorials on how to work with light tents are your best bet.

Good luck!

edit: I wanted to add that you will typically use 'gobos' or 'light blockers' to prevent light from hitting the object where you want it to appear darker. So in your 'how to make a white shoulder look dark' you're going to place a black piece of cardstock near the object so that less light reaches it.

Much of that can also be fixed in photoshop. There's a reason 'ring flash' lights work well for certain types of looks, as well. Lots to learn here- and you've got a willing model to work with :)