l was watching critical roll (minor spoilers for ep 29) and caleb used his scroll of invisability without transfering the spell into his spellbook because of a lack of magic ink and paper.

My question is: lf he had normal ink & paper,could he have made a non magical copy of the spell so he could use the spell and still be able to copy it to his spell book later?

That would be a DM house rule. It is not how the rules say.

I think that the fact that you can't even make a "normal" copy of your own spellbook in this way means that the answer to the question is likely no (it still costs time and money), but I'm not entirely sure. 

Rote copying a scroll in this way would leave you with a non-functional copy, and it seems that the intent is that when you find spells and want to copy it into your spellbook, it needs to have been in functional form (for at least someone, such as whoever wrote the book).

ok, but what about the item requirement for transferring? it says you need 100G of ink and paper,but what is the ratio? 100G of paper and 100G of ink? 90G ink 10G paper? 50/50? if l had 100G worth of fine ink and only a silver worth of paper would that work? what about 100G worth of fine parchment and a vile of ink l just got by "milking" (inking?) a squid?

It is irrelevant. As long as the total quantity of materials is valued at 100gp, that’s all that matters. It doesn’t even matter if it’s only that expensive because of price gouging. All that matters is that the “value” those materials hold to the character = 100gp. The materials are less important than the value the Wizard places on them. Value=Magic

That would be a question for your DM.  Personal opinion, I'd allow to make the non-magical copy no issue, but when you later come back around to try and actually copy it for real, the DC for doing so would be higher, and the cost in materials would be higher, since you've inherently lost some of the important information to make the spell actually work and have to trial-and-error figure it out.  Perhaps also have an outcome of that DC be that the spell only sometimes works properly, and other times it misfires.  And the spell will continue to do so until you spend time trying to fix it, and eventually beat the DC.

From the 'Your Spellbook' sidebar on the Wizard page in the PHB (note this is also how spell scrolls, which are "written in a mystical cipher," are copied): "Copying that spell into your spellbook involves reproducing the basic form of the spell, then deciphering the unique system of notation used by the wizard who wrote it. You must practice the spell until you understand the sounds or gestures required, then transcribe it into your spellbook using your own notation. [...] The cost represents material components you expend as you experiment with the spell to master it, as well as the fine inks you need to record it."

Neither the ink nor the paper is magical. You don't even need paper, really, but what material components are you really going to expend on copying spells that don't have material components for you to use up while practicing the spell? Also, it's ink -- you can't erase it (technically, you can scratch it out, but eventually you'll wear a hole in your paper, even parchment), so it's best to do all that testing on scratch paper, and once you've got the spell all figured out, in your own notation, you then copy what you've figured out over 8 sheets of notepaper, covered in blotches and crossed-out bits that don't work, into your spellbook, where it's nice and clean and now in Zemnian and maybe Celestial instead of Common.

Also, Caleb had the Keen Mind feat, and could have theoretically memorized the spell from the scroll and been able to recall it with perfect clarity for a month, but I want to say that was specifically not allowed.