ATTACH PAPER SKETCH TO A CANVAS, HOW TO ?

I would take it to a service that does "Giclee" printing on canvas, they will copy your original work and reproduce it as an inkjet (a high end version like an IRIS) on canvas. You can sign it as a "1/1" , a mono print.

I appreciate the idea, but I promised the girl the original and I don't have the time/money for that.

Then all youve gotleft is to trace or project the entire work and redo at whatever scale the client wants. (I always work in stages with clients. Ill do a basic layout sketch and develop an "approval" Then would I go and create my "masterpiece". I would usually develop a finql sketch and then have it copied in B&W on my selected paper or board. That way I hd maybe 5 copies of an outline of a sketched or inked "final layout" on which I could work till it pleased me .

Youre now gonna have to do the thing all over (if you are seeking to doing an original)> You should read Norman Rockwell Illustrator by Arthur Guptill. Its a 1949 book that has NR explaining how he does work for illustration (which is what youve just entered the field of).
He would have his work copied and/or blueprinted on Ammonia sheets and would overlay onto his canvas, a "photo negative" by sensitizing the canvas.

He did a lot of tricks that Ive copied nd learnt from during my days as an art student. It really saves time qnd keeps you from becoming bored with a work (Rockwell said he "pitied" the younger illustrators who would do their "finest work" at the outset ind then be exposed to a magazines editorial board who would deflate your self esteem with "nickle dime" comments and chqnges (THEY ARE THE CUSTOMER). The way Rockwell worked (he said) was to gradually work up to his finest final work. This saved time , materials and made each ascending work not become a bore.

Youve learned a lesson in art as a BUSINESS as well as a passion.

PS dont even consider doing a "paste up" like Frazetta did on some of his. The works wont last without significant intervention every few years.

s Norman Rockwell said (qnd I paraphrse)
Your best work of a subject is your FINAL version , not your first IF you insist on "mounting" it on q black canvas (AAgggghhhh) make sure you get a good archival glue (I hope youre on acid-free archival paper)

sa you might try rubber cement; though of course it would be difficult to remove later from the paper

Someone should OP diff kinds of glue and appls for ea

NO NO NO, rubber cement iw not for mounting art work on papaer. Itll ruin a pencil sketch. You just might wanna use archivl double stick tqpe.

trust me, Ive done this for a living

Oh I do, Man, implicitly. I withdraw my suggestion

Vega if it's not too late I wonder whether you might have considered a spray glue, making application quick and uniform

Farmerman is the one to listen to.

Probly so. Ah well I try

This Is to our OP

I was thinking. If the client wants it on black canvas, she wont necessarily care if you make it look like you planned it that way. Why not try to celebrate the mounting rather than finding a way to do it while not harming the paper.
Are you familiar with the little corner mounts that are like corner paper tab "sleeves" Into which the corners of a photo are embedded. No glue, just a while corner tab that is stuck onto the canvas. You can then mount the drawing on a sleeve that is also affixed to the canvas.
I dont like to have you "Glue, or paste anything that touches your work. It will really ruin the pictures paper in time (Glues will attract all kinds of molds an it will cause "foxing" , it will discolor the paper at some point and will probably take the sizing out by slow chemical erosion. Archival tape will , of course, dry out and brek up in 10 years or so..

Mounting i tuff. I suppose the client wants the canvas to act like a mat . Try to convince her that its gonna be a mess in 5 years unless you use those corner tabs. I think they still make them in colors too.

Heres what I mean by "corner tabs"> These are in black and can apparently be acquired on the web in many different sizes. Im gonna have to use them sometimes when I want to make a print mount look kinda "industrial"

Had occurred to me Man but you beat me to it

Why not have this one-of-a-kind paper artwork mounted with floating attachments , then put into a frame? I did that with a family recipe that was written by mother, now deceased. Turned out great and protects the original piece.