Creating a High Dynamic Range Image

[Raoulk]

Hi Guys,

I was wondering if it is a good idea to create a HDR image using the automate -> merge to HDR Pro using photoshop especially for interior visualization.

Here is what I tried to do:
1-I rendered an interior image with the right exposure, then saved 2 brighter (+1.5,+2.5) and 2 darker images (-1.5,-2.5).
2-Added them to Photoshop using the "merge to HDR Pro"

Here is what I got:
1-it worked in one render out of 4 (the others just looked crazy and not right at all)

Question:
Has anybody ever done it? if yes, is it the right way?

Thank you for your expertise,
Raoul

[romullus]

Why don't you simply save your render to EXR, or HDR format? Corona and pretty much any other renderer renders in high dynamic range natively, you don't need photoshop to get HDR from its output, it's already there.

[Raoulk]

Hey Romullus,

I did not know about it! thank you for the tip.

It is a 32 bits, that means that some blending modes are not available.
I was trying to keep in the 8-16 bits to get the full capability of photoshop.

Switching the mode to 16bits would ruin the HDR right?

Thank you for the reply

[romullus]

Yes, saving to 16 bit will destroy high dynamic range, unless it's 16 bit in EXR, which would not help you with photoshop blending modes anyway. On the other hand, why do you need photoshop? Perhaps, there's some other workarounds to do what you want, if you could tell us what you're trying to achieve.

[Raoulk]

I like to make visualizations realistic to what the viewers are used to - that could also mean what the market is used to in the region. For example, when they are listing a real estate, they use HDR images to show the interior balanced lighting and shadows especially for dark rooms.

I like photoshop because of the advancement in AI generation and the layer based model. I use several additions in collage mode for example and do not rely solely on the output from the rendering software. I believe it is faster to do so.

32 bits is something that I tried in the past especially for reflection, shadow and refraction passes - the downside is that the region render or if I want to fix something from the rendering software, it is so hard and then I would have to render the whole thing again.

This is why I started by using the 2 extra exposure values up and down to achieve a 16bit from a PNG output with all the blending modes etc.

[romullus]

I might misread your original post. When you said "2-Added them to Photoshop using the "merge to HDR Pro"", what is the output of the operation - 32 bit high dynamic range image, or tone mapped 8/16 bit low dynamic range image? If it's the former, then saving the render to EXR, would just save you additional steps in photoshop. I don't use photoshop, so i don't have much clue how it operates.

[Raoulk]

I will try to do so then, thanks!
What image software do you use?

Thank you

[romullus]

I use Affinity Photo - 90% of photoshop features at a tiny fraction of its price.

[maru]

Looks like this Photoshop feature turns multiple exposures into what was known as "HDRI" in 2000s photography:
https://www.adobe.com/learn/photoshop/web/photoshop-merge-to-hdr?locale=en&learnIn=1

There is probably nothing wrong in using it for artistic purposes if you find it convenient, but I doubtany of the famous studios and artists use it. :)
You should be able to get similar results by making adjustments to 32-bit EXR files as Romullus suggested. Or perhaps you can get the results you need right in the Corona VFB?