Plumbing Your Drawing/Painting -414

Paul talks about the use of the plumb line and the importance of vertical in one’s work. He discusses how the relationship of all angles to plumb is the beginning point for assessing them and their relationships to each other finishes bringing them into conformity to the big impression.
QUESTION: Is it permissible for you to use the plumb line before you start drawing? I mean, not so much to find the vertical correspondence between two or more points, but to see how far a given line deviates from the vertical. Practicing drawing from the glass according to Anson Cross' suggestions since November last year, sometimes I notice that there is already a definite vertical line near or within the subject I am drawing (the line joining two walls, the frame of a window or the leg of a table) and in that case I compare that line with the other lines in the subject, sometimes, however, there is no vertical or there is a line that looks vertical but is slightly slanted, is it permissible to use the plumb line in these cases?
Thanking you in advance,
Carlo

[@threetenticlesforward]

Congratulations Mr. Producer on your new addition 🎉

[@TonySwaby]

Every time I catch one of your videos you confirm everything I say. Remarkable, thank you :)

[@querenstewart9944]

Hi Paul
Thanks again for this enjoyable experience a delight as usual
Sheila

[@christophercahill592]

‘The Cellist’ is so lovely from the faithful toiler

[@SkjtheartistJamison]

My father was a sign writer and permanently had a plumb line in his hand. He coated the cord in chalk and twanged it like a guitar string to get his verticals. When I first started painting seriously I used the same technique. Eventually, experience negated the necessity of a physical line

[@RobBaranko]

Hi Paul,
In previous videos, you mention what the Boston School guys are “after” (visual order, majors and minors, overall effect of light and shade,etc.) and I believe you say that guys like Sargent are “after” something else. I enjoy the parallels you draw between the Boston painters and people like Sargent, Zorn, and Sorolla, so I would love to hear your thoughts on how their objectives might differ, and how this affects their way of working.
Many thanks,
Rob

[@fuseblower8128]

Personally I feel it's very easy to introduce a slight slant in all vertically oriented lines which is not obvious to my eyes. The remedy is to look at the mirror image of the drawing and the slant becomes painfully obvious. It's like a 89 degrees line reads as vertical to my eyes but its mirror image of 91 degrees reads as obviously non-vertical. Of course, being aware of this "blind spot" makes me extra careful. Perhaps that's why the poster of the question likes to have a vertical, as a kind of reference.