Those are lovely.
Photo's can be a bit hard but natural light works well. I like to lay things on a neutral background that allows high contrast. Dark for light objects and light for dark objects. Fabric is fine. A strong sidelight helps. For my bowls I made a station where I hang fabric down a vertical wall and over a Small table. I slip a small book, block, or box under the fabric as a pedestal. Then I use a clamp on work light to provide a strong light from one side. I take several photos with that light in different positions till I get what I like then start rotating the bowl.
Something that might be cool for arrowheads would be a support that is under the fabric or covered in the fabric. Maybee a little support bracket made out of clear plastic? Swing by your local sign shop and ask them if they have any small pieces of acrylic in the scrap bin. They may also have MDO scrap which is a high grade of plywood that makes great jigs and cauls
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