This shadow simply doesn't look authentic, how to fix?

Forum|Forum|7 years ago
November 20, 2018
5 replies
2304 views

Hello to all of you,

I am having trouble making the shadow in this picture look authentic.

Can the thickness even be this much?

Am I blurring it too much?

Thank you in advance for the help!

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Correct answer rayek.elfin

There really are an infinite ways to light this. A couple of quick renders in Blender:

First three are a simple point light positioned directly above, at varying sizes (or distances). The smaller a light source, the sharper the shadows will be.

The 4th one is equivalent to out Sun's size, overhead.

The ones after that I used an environment lighting (HDR) which simulates 'real' lighting conditions. The final one is a simple spot light, aimed from an forward angle.

Then there's the contrast as well to consider. It really depends on the lighting conditions you would want to emulate.

rayek.elfin

Legend

Here's the Blender file in case you'd like to test this for yourselves. It produces this version:

http://www.upl.co/uploads/shadows1542787142.zip

D Fosse

Community Expert

...which illustrates my point perfectly

The OP doesn't need to simulate any particular conditions. He just needs something credible, so an abstract of Rayek's (all of them except 4 and 8). Or mine, which was entirely manual.

D Fosse

Community Expert

The shadow softens the further away the object is from the surface:

Trevor.Dennis

Community Expert

There is not enough information to say exactly how big and far away, and what direction the light source is coming from.

This example assumes centre and in front of the zip, and fairly small (tiny Shadow Edge Transfer).

The shadow will be harder and denser where it is closer to the zip, so darker towards the edges.

Dag's example in post #4 assumes a large light source directly above the zip, so a huge Shadow Edge Transfer. In practice we probably wouldn't light exactly light this, because the lens front element is likely to be hit with direct light causing flare. A lens hood and careful use of flags (black card) will prevent this, but it is easier to move the light towards the camera, and tilt it towards the target.

Doing this sort of thing with Photoshop is best done with multiple layers (at least two), because it makes it so much easier to achieve the different shadow properties. We can make use of Mask Properties.

I paint the close in hard shadow with the paint brush, which is tricky to get just right, but being on a separate layer I use the blur and smudge tools to soften and drag the shadow into best position.

I'd love for davescm to do this with 3D and render the shadows.