Does The Plastic On A 1960S 14 Differ From A 1970S 225? (Infrared Photos)

**KBeezie** · November 25th, 2018, 01:10 AM

I originally discovered some of the vintage plastics such as in my 1964 Pilot super 250 were transparent or highly translucent under infrared light (especially once you cut out all the visible light such as going above 800nm).

This is my Montblanc 14, under 1,000nm infrared (absolutely no visible wavelength at all), the section has some mild translucency but not nearly as clear as the rest of the pen.

The 14 is currently inked with Montblanc Irish Green.

Under normal visible light

And then there's my Montblanc 225 where even the section is very transparent.

So I'm curious what was different with the plastic back then that allows for so much infrared wavelength to pass thru, as most of the black plastic now days doesn't seem to allow much to pass, or if it does it's very little (like with my Sailor 1911L, still close to opaque but you can make out the outline of the content within).

**FredRydr** · November 25th, 2018, 10:08 AM

I don't fully understand what you are doing. You expose the pens to the wavelength of light you mention, but what are you using to capture the images? Infrared film? Camera with digital sensor? If the latter, do you immediately see (live) the images you've posted above, or does it require some kind of image software? Sorry, but my mindset is still stuck in Kodak and Agfa.

**azkid** · November 25th, 2018, 11:24 AM

Digital camera sensors are sensitive into the infrared range. Manufacturers typically install a filter that blocks infrared and beyond.

But if that filter is removed and another that blocks visible light installed (interestingly, an unexposed, developed, 35mm film negative will do this) then your digital camera will only see infrared wavelengths.

(I only know this from as some robotics and electronics projects I've been involved in over the last several years)

Meanwhile, is it the plastic or the coloring used in the plastic, I wonder? Fascinating test.

**KBeezie** · November 25th, 2018, 03:17 PM

Originally Posted by FredRydr

I don't fully understand what you are doing. You expose the pens to the wavelength of light you mention, but what are you using to capture the images? Infrared film? Camera with digital sensor? If the latter, do you immediately see (live) the images you've posted above, or does it require some kind of image software? Sorry, but my mindset is still stuck in Kodak and Agfa.

An Olympus E-M1 (first generation) that was modified by LifePixel.com (https://www.lifepixel.com/introduction their website can explain the process) to "Super Color IR", meaning they replaced the UV/IR blocking glass the manufacture puts in with one that can see 590nm onward, I can then further add infrared filters on the front of the lens to cut down what the camera sees further.

Most digital cameras are capable of seeing from ultraviolet (down to around 200nm) up to about 1100-1200nm into the infrared spectrum, but it often shows up as undesirable purple fringing in photographs since most lens do not bend UV/IR light the same way as infrared light, so the focus is shifted and creates a purple/red halo or fringe around objects. So the manufacture typically puts in what they call a hot mirror that effectively blocks both UV (starting around 400nm) and blocks Infrared (short of 700nm) so that only visible light is shown to the sensor.

My modified camera doesn't have the deep orange/red onward blocked.

The lighting source is simply the studio strobe which does give off some infrared light, the daylight balanced LED bulbs in my room though do not show up, whereas incandescent bulbs would give some light off as they're not made as energy efficient to limit it's output only to visible wavelengths.

Originally Posted by azkid

Meanwhile, is it the plastic or the coloring used in the plastic, I wonder? Fascinating test.

I would say the plastic itself, as if it was just the dye, then the plastic wouldn't be penetrated by the wavelength. Though I noticed that the material Lamy uses for their 2000 is completely opaque.

It is nice though to be able to see how the nib is being held in on the 225 or to look in and see if there's any threading for the purpose of disassembly, or to check for cracks or trapped ink pools (glad I don't have either of the latter on the 225).

Some lens do have hot spots under infrared (bright circle in the middle), my old Tamron adaptall-II (from 70s/80s) 90mm f/2.8 1:1 Lifesize macro fortunately does not, at least when cut down to deep infrared. The pictures at the top of the thread were from my old Pentax-M 50mm f/1.4 adapted. I seem to get the most favorable results with my 1951 Canon Serenar 35mm f/2.8 Leica Thread Mount lens.

**FredRydr** · November 25th, 2018, 04:26 PM

Wow! Very cool. I like the mix of new and old optical technology.

**KBeezie** · November 25th, 2018, 08:00 PM

Originally Posted by FredRydr

Wow! Very cool. I like the mix of new and old optical technology.

Most of the newer lens, are either 1) way more expensive for the same thing, or 2) have some coating of their own in order to cut down on UV/IR wavelength on top of what the camera body may or may not filter in order to improve quality to most consumers.

If you ever pick up an old lens that has the distance scale on the lens (or a very high end newer lens) You may see a red mark on the focus scale a little off set from the center (or multiples if it's a zoom lens).

That red mark is where you have to change your focus when working in infrared, and was common enough that manufacturers marked it on the lens either for technical or artistic use such as using Kodak's HIE (high speed infrared) film. Or using a deep red to infrared filter with film that supports it (Ilford SFX 200 film for example can see both visible light and infrared), the problem is in a SLR if you focused on visible light, it'll be a bit out of focus on the infrared. Though without a filter, the visible light usually overpowers the sensitivity of the film like SFX that you don't register the fuzzy part (much the same way why some unmodified digital cameras can see a tiny bit of near-infrared, it's overpowered by the sensitivity of visible light until you filter out most of it with a shallower filter like a 695nm or 720nm filter, higher than that will be black on an unmodified camera)

When I had a BW 092 (695nm onward) filter on my Olympus E-M5 (not modified) during an overcast day and some photoshop tweaking to pull the colors I ended up with this :

I went back to the same spot a couple months later when I ended up with a modified Olympus E-M1 at night during a clear night (so that the sunlight reflect off the moon would light the scene with long exposure), but to my dismay they bulldozed the place so I took a picture anyways as a panoramic.

The two tone/color look is usually usually because one is infrared (usually the light that shows up off foliage/leaves/etc) and the other half is visible light (usually the deep orange/red end of our visible spectrum), and from those two differences you can usually swap or tweak the color representing either infrared or visible light. On an unmodified camera like the first picture, the results are a fair bit more muted, and needs to be pulled out a bit.

**KBeezie** · November 26th, 2018, 08:36 AM

The Montblanc 225 section with just the nib attached (feed/gasket removed) after rinsing it. An example of shooting without the 1,000nm filter in front allowing for a mix of visible light and infrared light, and some tweaks in photoshop to increase the color separation between the two. (the camera is a 590nm converted camera, so the visible portion is just what we would see as deep orange/red).