What’s the difference between [v] たとしても and just the plain ても? Example:
The difference between these two hinges on whether or not the action has been completed at the time the statement was made:
This could be taken in one of two ways:
Even if you (I) read the instructions, it will [still] be hard to understand.
Even after reading the instructions, it is [still] hard to understand.
So with the ～ても form in this sentence, the action (読む) may have already taken place, or it may be a hypothetical action to take place in the future.
By contrast, the ～としても pattern always refers to a hypothetical situation which may or may not take place in the future. As such, the translation "even supposing you were to [action]" often works well for ～たとしても:
Note that while both ～ても and ～たとしても can both express hypothetical cases, ～ても better matches a "even if … will" pattern, while ～たとしても better matches a "even supposing … would" pattern in English.
I may be wrong about that, but I think
(た-Form)としても has an extra sense of supposition, while
～ても has a much more 'real' feeling (in the sense of realis).
I'll take YOU's examples, which I understand (and would translate) quite differently. In the most literal sense, they spell to me as:
Reading the instructions, this is still hard to understand.
Supposing one reads the instructions - this is still hard to understand.
There's actually no focal (emphasizing) "even" in either of the sentences in Japanese. If you want to emphasize that that reading the instructions was supposed to help but didn't really help you, you can use たとえ:
Even though I read the instructions... Even if one reads the instructions...
Even if I - let's say - read the instructions...
Since I've moved to a less literal translation here you can notice something else: (1) easily translates to both a simple concessive statement (although X happens, Y happens too) and a concessive condition (even if X happens, Y will also happen). When we get to (2) on the other hand, it can only be a condition - that's is because
～たとしても is a supposition so it can only be used to describe hypothetical situations, not something that actually happens now or has happened before.
It's hard to understand although I read instructions.
It's hard to understand even if I read the instructions.
〜ても also has some sense like としても, if you use like
読んでも分からないと思う (I don't think I will understand it even if I read it)
There is an implicit premise in としても expression.
Here, the premise is that the instruction is supposed to help the reader/user.
(But, this equipment is way too hard to operate); even a (helpful) instruction (if any) cannot be of help.