[Filter Test SEU Gen2 #6] Monochrome Museum Comparison

[Andrea B.]

Surprising to some perhaps, I do not have any Subtraction tools! I don't use Photoshop.

 

However, the BaaderU and the SEU Gen2 are always going to record the Rudbeckia floral signature very slightly differently because the Rudbeckia reflects UV on its petals at approximately 350 nm around which the BaaderU will capture more around 350 than the SEU Gen2. They both capture the Rudbeckia UV-absorbing areas the same in terms of outline. All flowers are different of course, so we don't know how it will play out for other flowers -- or subjects -- which have a different UV-reflecting peaks.

 

I will get back to this in a few days. I have to sign off soon for a while due to some other activities I'm involved in.

[dabateman]

Funny, the first software that came to my mind was ImageJ. I guess that shows more of my background. I still want to try this with a couple subjects and see if there are differences.

Even if I had Photoshop, I wouldn't know how to do that subtraction.

The free ImageJ is by far better, insert smilly face here.

[Cadmium]

Andy, 'eh', would you like me to invent a cute little nickname for you?

Andrea, I really hope your horse makes it...

I was being serious here, you two, and we should be respectful of each other and not make fun of each other, right Andrea?

 

Andy, "the problem"?

I just though maybe you might show me an example of what you are talking about since I am not set up to do that like you are.

[Cadmium]

I will return to my idea of the Photoshop 400nm+ subtraction as being a valid method of subtracting the 400nm+ out-of-band blue/violet content from the UV shot.

http://www.ultraviol...dpost__p__22884

 

In conclusion, the SEU filter transmits more blue than any other 'UV-only' filter, except for those which are made to do so.

So I can not categorize the SEU filter as a UV-only filter, because it contains so much 400nm+ blue/violet.

As with other UV+Blue filters that cross the 400nm line, the added blue/violet shortens exposure time.

 

The best test of the SEU I have seen is the bandpass test that Jonathan did, comparing the Baader U, SEU and La La U,

clearly showing how much blue/violet 400nm+ content the SEU has.

http://www.ultraviol...dpost__p__22919

 

I also find interesting how the 400nm- bandpass filters show the same overall brown color tone that the subtracted version I made shows.

I don't think that is coincidental.

The 400nm+ blue/violet content of the SEU is adding to the exposure and color tone of the shot

[Andrea B.]

I'll try to find a subtraction tool. Sorry I don't have one to help out with such tests!

 

I strongly suggest you start a new topic to contain this one specific violet leak investigation. It will get lost in this topic which has "Monochrome" in the title. Many people do not fully read through all posts in topic. Only the first post usually. Sad perhaps, but true.

[Andy Perrin]

New topic here:

http://www.ultravioletphotography.com/content/index.php/topic/2908-filtering-by-image-subtraction/

[lukaszgryglicki]

Can't see photos in original post (similarly in other posts listed for SEU2 in the first post).

 

[Andy Perrin]

Strange, they are showing up for me?