On the Prowl in McDowell County

[OlDoinyo]

The first image was shot seven years ago with the Minolta Autocord and Ilford Delta 3200 film. Note the darkening of the trestle standards and the logo paint on the locomotive due to titanium dioxide pigment. I chased this train down the Mill Creek valley and hurried to set up on an overpass so I could snap this photo.

 

"Coming into Town"

 

The next three images were taken yesterday, with the Sony A900, the Baader U2 filter, and the Steinheil Cassar S set to f/16. Display intent is BGR.

 

The thing to notice about the first digital image is that the paint on the buildings shows no particular coloration (other than a rosy tinge from the low sun.) From the 1750s through the 1970s, the dominant pigment in paint sold in the US was lead carbonate, which is UV-bright. As realization of the toxicity of this paint came to light, manufacturers switched to titanium dioxide, which has strong absorption below 380 nm and usually shows as strongly colored on photographs such as these. What do you want to bet that these buildings still have the old paint on them?

 

"Old Paint"

 

On the next photo, the "POSTED" placards (legible only at full resolution, not here) show a bluish background, indicating that they are more UV-bright at short wavelengths than at longer ones. This is at least mildly unusual for man-made materials. The placards appeared yellow to the eye.

 

"Forbidden Country"

 

The final image shows a rosy glow from the vicinity of the sun, which was just out of the frame behind a ridge to the left. The new vegetation growth shows distinctly rust-brown. You would hardly guess that these images were taken on an exceptionally clear day, with visibility that is uncommon in this part of the country.

 

"Evening at Dink Cannon Junction"

 

Some of the images showed concentric bullseye patterns that are not part of the image proper; I suspect a light leak in my filter adapter, but am not sure.

[JCDowdy]

"Old Paint" is a reflected UV photograph?

[OlDoinyo]

"Old Paint" is a reflected UV photograph?

 

It was taken through the Baader filter, and there are no light sources in the frame, so yes.

[Andrea B.]

What do you mean by "display intent BGR"?

Thanks.

 

An interesting series of images. Very nuanced.

[Alex H]

The last two images are too dark on my monitor, so I have difficulties understanding them.

[Andrea B.]

Yes, they are very dark.

There are a lot of stops between sky and landscape in UV shooting. We have to choose one or the other, it seems, unless two exposures are layered to preserve both. Or unless the dark areas are lifted in an editor.

[JCDowdy]

It was taken through the Baader filter, and there are no light sources in the frame, so yes.

 

The red color of the SUV under the tree and the fact that it remains visible through the windshield of the car parked in front of it seems inconsistent with a reflected UV image. I had thought perhaps this was one of your fascinating GBU composites, but the colors look to realistic.

 

Please don't think I am picking on you, I actually like the photo. It reminds me of my folks' place, my Dad used to have a red Jeep Cherokee and that tree is grand! So, don't take offense, but have you perhaps mistaken which Baader filter you used?

[OlDoinyo]

The "red" Jeep was definitely not red to the eye. It appeared bluish in the image that came out of the camera and I don't remember its visible appearance--some pastel greyish hue, maybe? "Display intent BGR" is shorthand for: the "blue" channel is displayed as red, the "green" channel is displayed as green, and the "red" channel is displayed as blue. This has the effect, with this sensor and optical train, of tending to display the shortest wavelengths as blue and the longest as red. (I say "tending to" because there are of course no real separate channels.) As some others use different display intents, that is likely why it appears strange. I guess the sky light is technically scattered rather than reflected. I looked at the second parked car in the original image, zoomed in, and all I clearly saw in the windshield was reflections of the tree above.

 

I only own one Baader filter, and it is quite impossible to confuse it with anything else in my kit; nothing else I have looks remotely like it.

 

The image darkness problem I have run into before: it is a color management issue. I have some calibration hardware on order and with luck I can recalibrate my monitor soon. The images look at least a stop darker on my smartphone than they do on my master monitor. I am sorry about this. I did some curve tweaking in all three digital images to knock down highlights and expand shadows.

[JCDowdy]

Sorry for being so dense, I see now I failed to understand what "BGR" was!

It is interesting how it renders more natural colors to the image, especially the foliage in the background.

The red in the windshield really threw me, thanks for your patient explanation.