I have a feeling that numbers 13-15 have the wrong dates on them. This type of fading is reminiscent of the original dye-bleach Kodachrome process, which ended about 1938. The rest of them have the usual look of old K-11 Kodachromes.
They are also the only ones that seem to have been made using some kind of artificial light source or flash... maybe the color shift in these specific slides is just the consequence of a non-daylight type light source?
Thanks for pointing out these images. Really enjoyed viewing them
I have a book in my loft dating from 1910 called Spectroscopy, printed in London, England. It gives full instructions about how to build a spectroscope from scratch (as laboratories had to back in those days) AND prepare, expose & develop colour glass plates from a technique devised back in 1906. Luckily Kodak's colour film is and was much easier to process.
If anyone is interested I have a slideshow of color pictures taken in Germany circa '39/'40 in a email.
I dont know how to get the pictures singled out of the email (not much of a computer guy) but if you want to see them I can forward it to you. Just let me know where to send it.