In Grimm there appear to be two types of Woge, one that normal people can see and one they can't. What is the difference between the two and what are they called?
There is no separate name for the varying levels of Woge, though it has been called a full-on Woge when normal humans are able to see the transformed states of Wesen.
A "lesser Woge" can only be seen by a Grimm or other Wesen. It can be a reflexive response triggered by fear or surprise. It is a split second display.
Woge can occur in different degrees, a higher degree of woge yielding a more complete transformation. In the Woge state, the Wesen has access to it's animal form abilities, including strength, speed or other unique abilities.
A particular Wesen, the Jägerbar, has even been observed in a complete transformation into a grizzly bear after first removing her clothes. Most Wesen will only partially transform for a limited time.
The Woge state is a transformation without a complete explanation, since injuries achieved in the human state don't always transfer to the Woge state and vice versa. It is also possible to lose the ability to Woge or lose the ability to retract the Woge state remaining permanently in the transformed condition.
Many Wesen have been observed partially transforming, and most known Wesen have been observed transforming only to a degree detectable by a Grimm. Blutbaden, Coyotl, Drang-Zorn, and Balams have demonstrated being able to shift partially by localizing the woge around their eyes. Blutbaden's eyes turn into a fiery red, Drang-Zorn's turn green, Balam's eyes turn amber, and Coyotl's eyes glow bright yellow. ("Bad Moon Rising") ("The Bottle Imp") ("La Llorona") Others have only partially woged before, such as Doug Shellow, a Mellifer, morphing only his arm. ("Beeware")** --Grimm Wiki > Woge
From what I've seen, such as when Bud had accidentally Woged for Juliette (Bud seemed embarrassed at his accidental full-woge) near the end of season two, I believe that the Woge is an emotional response, and if a Wesen does not retain focus, they can be seen by anyone. Monroe also said to Hank that the two versions of Woge are
- Emotional agitation.
- Heightened anger.
I'm pretty sure that an intentional Woge requires the control of one's emotions. For example, since there would be no practical reason for, say, Baron Samedi, to Woge if he isn't spitting, it might be a matter of Wesen making their emotions 'believe' that they need to be Woged (Try to think of Wesen as actors who needs to make themselves cry for a specific purpose, which could be done by thinking of very saddening things).
That was not what I understood from what was said on the series. My interpretation is that a Wesen can change but he needs to chose to be recognized or can "loose control" of the transformation and be seen anyway.
The fact of injuries when on Wesen form are not transferred to human form, for me was a plot error or budget problem (Wesen are visual effect, makeup, etc) and human are not.
Also I think that the "degree" is only related to the abilities the other factors degree of transformation shown, etc are survival instinct as they are weaker the others.