Driftwood, Texas

[Unscenerie]

Hello folk,

I present you my latest false color UV edit from my trip this summer to San Antonio from Houston.

 

Shot with Sony A7 FS, Soligor 3.5/35.

Tangsinuo's ZWB1 + TSN575.

ISO 125, 10s, and f/8, I believe. I try not to shoot at wider aperture than f/8 as the corners get soft with this adapted lens. The heavy vignette I seem to have a hard time with.

 

Post: Photoshop Raw - custom WB, color and channel mixer.

Photoshop - channel mixer.

 

I'm aware that members of UVP prioritize properly white-balanced UV photos, yet, I've been grinding Photoshop to get the most interesting false colors. 

- I'm posting white-balanced photos done in Darktable, temp. 3014 K, tint 1726, not sure if that's proper WB.

 

Happy New Year! I wouldn't have made it this far without you all.

[colinbm]

Interesting photos of a great subject.

[Andy Perrin]

Very nice. 

[OlDoinyo]

[deleted]

[Andy Perrin]

9 hours ago, Unscenerie said:

I'm aware that members of UVP prioritize properly white-balanced UV photos, yet, I've been grinding Photoshop to get the most interesting false colors. 

- I'm posting white-balanced photos done in Darktable, temp. 3014 K, tint 1726, not sure if that's proper WB.

 

That is only true when we are trying to understand something technical about a photo (e.g. diagnosing out-of-band contamination, hot spots, etc.) because it makes comparisons between photos and enables everyone to develop some intuition about how a "standardized" UV photo is supposed to look, the better to detect problems when something doesn't look "right." For artistic purposes, it's always a blank slate, although it's good to tell people what they are looking at or you will generate confusion! Long paragraph short, don't worry.

[Nate]

Color looks great, just wondering what version of darktable are you using. I'm still on 4.0, haven't dowloaded 4.2 yet. Curious if it's any different.

[Unscenerie]

@Andy Perrin gottcha

 

@Nate I'm using Darktable on Mac, version 3.8.1. 

How would you white-balance these 2 photos? Would you place the eyedropper on a certain area or drag the sliders around to get a natural look?

[Nate]

With the dropper, I draw a square in different areas, sometimes you can just make the dropper square the whole picture.

 

Another way to play with the colors is to change the input to LAB, and it makes the purples more blue

here's lab input

 

[Nate]

I missed in your comment you asked where I'd WB your photo, raws work the best but did mange to get different WB on your jpeg. It's all up to preference I think for non scientific work, but this is where I put it

 

[Andy Perrin]

The best way to white balance is off PTFE/teflon or similar, and transfer the white balance to other photos taken under the same light and camera/lens/filters. That’s if you care about trying to get rid of the color cast 100%. It’s also pretty easy to do in practice so that’s what I usually do. 
 

If you don’t care about getting it perfect, you can use anything magenta in the original photo and it will work pretty well if it’s the RAW. 

 

White balancing on a JPEG is very hit-and-miss and I strongly recommend not trying to do that. It will work ok sometimes but not others. 
 

—

By the way, don’t make the mistake of thinking paper is white in UV. It is not usually white. (Only Stefano seems to have some magical tissue paper without the fluorescent compounds that make it absorb UV.)

[Stefano]

17 hours ago, Andy Perrin said:

By the way, don’t make the mistake of thinking paper is white in UV. It is not usually white. (Only Stefano seems to have some magical tissue paper without the fluorescent compounds that make it absorb UV.)

You have reminded me that I should get some PTFE and do a comparison. If you try a tissue paper, do you get a color cast?

[Andy Perrin]

Stefano, I haven’t tried our local tissue paper. It may also be brand-dependent. Every other kind of paper I have seen does fluoresce however. 

[dabateman]

You could bring a uv flashlight with you the next time you go paper buying.  Then look for a non glowing one or brand to test. 

See if the art supply store employees give you odd looks.

[photoni]

All the A4 copy papers I use have brighteners which are highly reflective in the UV.

Watercolor paper or cotton art paper do not react with the Nemo 365 nm torch.

In my tests I have seen that Teflon works well (panel and plumbers tape) but they are also too bright,

better anodized aluminum or even the old classic 18% gray Kodak cardboard

[Stefano]

Yes, brightness can be a problem. I set my white balance in-camera, but if you want to include the white reference in your photo and white balance it later, you may overexpose it, especially in UV.

[Andy Perrin]

Photoni, what evidence is there that ancient 18% gray cardboard reflects UV uniformly? 

Anodized aluminum isn’t too bad though. 

 

I have never had any trouble with PTFE overexposing in the RAW. Only in JPEG has that ever been a real issue. And if it does overexpose? Stop down the lens! 
 

(And if you are shooting in-camera JPEG, that’s some poor decision-making…)