I wonder what exactly is the formula for collectibility rarity increase?

[gothikka]

I wonder what the formula for collectibility rarity increase is.
I know it's definitely not x1 perception as the tooltip for Methodical Appraisal makes it out to be.
Another thing I noticed, is that when you hit a certain amount of perception, then even when raising perception, it does not seem to increase rarity increase per hit.
Example: at 600 perception, using a Discerning Eye + Methodical Appraisal, get me +172 to rarity on a red cuperite node. This is the same for Adamantite as well as Red Quartz. Now I just melded my stuff and have 628 perception. I used some food and brought perception over 650. I still get the same +172 to rarity with Discerning Eye + Methodical appraisal. Is there a cap to perception in regards to collectibility related stuff?

[aerolol]

Yeah 172 is the max you can get from Discerning Eyes + Methodical Appraisal.
115 is the max from just a Methodical.

[Roth_Trailfinder]

I think the tooltips are worded very poorly for Appraisals. I think it is trying to state that Methodical is 100% Efficiency, and the other two are 90% Efficiency and 80% to 150% Efficiency. That Efficiency is based on your Perception, but we hare hindered in figuring out just how, what the formula may be, because of the cap on Collectability. Basically, at 100% Efficiency, the cap is 115 Collectability. Increase that 50% you get that 172. The other two Appraisals give corresponding amounts based on that cap.

That cap, combined with the number of swings on a Node, and the Wear on the item itself, make it something of a challenge to get truly high Collectability ratings with currently achievable GP totals. That cap, more than anything else, is the reason why people emphasize 600 GP rotations for Collectables. Reach that cap, and do these rotations depending on the desired Collectability rating (450, 470, 530, or low enough that you're not planning on using GP anyway).