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rto
07-08-2007, 11:30 AM
i think this applies to both oils and acrylics. there's times when i want to paint over and 're-use' a canvas/surface after i've already painted something on it before. but there's the texture and strokes from the previous painting and i'd like to somehow get rid of those marks and smooth the surface out before painting over it. any solutions to this?

TheBaron
07-08-2007, 11:46 AM
Yep sanding it down with fine grade wet&dry helps.

Done it many a time.:crying:

CareyG
07-08-2007, 12:33 PM
Be sure to take every precaution if you're going to sand an oil painting, it might not be a good idea if you've used any lead or cadmiums, etc.

You may find that it's more work than it's worth, though.

~!Carey

Ribera
07-08-2007, 01:20 PM
Common sense, but do make sure the old painting's at least a year since the last stroke was placed, as if it's not sceintifically dry you'll be painting lean over wet. In a year's time even the old picture's final glazes (if there were any) should be dry.
Of course, if you don't mind the new picture, in time, potentially cracking, go for it.

Ribera
07-08-2007, 01:25 PM
P.S. To eliminate old brush strokes, sand with a breathing/ventilator mask on. I've even heard it advised to pour solvent over before sanding, to eliminate toxic dust, but that was for flake (lead) white paints.
That shouldn't be necesary in your case. Wear the mask.

nit-wit
07-08-2007, 03:56 PM
Once I did this and painted over a portrait (note: no impasto, no large visible brush marks in the portrait!) - needless to say from some angles the "shadow" of the portrait's head was clearly visible! So maybe not a great idea if your work is anything like fine. In fact only do it if you're totally skint (as I was at the time). It's one of those mistakes you only make once - or should only make once. Putting a knife blade through a finished painting is another you only do once! Buy new canvas, it's not that expensive.

Best wishes,

nw

nit-wit
07-08-2007, 04:12 PM
Another thought...it may seem like a good shortcut to paint over another painting, removing the hassle of stretching, priming etc.

I was once asked by a student to show him a shortcut to being able to draw like the best Japanese cartoonists whom he admired. I had to tell him that they only got that good by hard graft, obsession and talent. None of which my student possesed.

Sorry I'm blathering, just trying to say that avoid sweeping the dust under the carpet, it'll still be there.

nw

TheBaron
07-08-2007, 05:27 PM
I was once asked by a student to show him a shortcut to being able to draw like the best Japanese cartoonists whom he admired. I had to tell him that they only got that good by hard graft, obsession and talent. None of which my student possesed.

nw

Whats this got to do with sanding down a perfectly good already stretched canvas?

RTO
Just sand it down and hold it up to the light in different angles to see if its flattened the oils thats already on it.

stapeliad
07-08-2007, 06:50 PM
You can sand it, then lay an oil ground over it. Do NOT gesso it, but I'm sure you know that already.

Also, if you're discarding the canvas you may want to destroy the image so some passer-by doesn't take a fancy to it and hang it in their living room. That happened to someone on here once.

nit-wit
07-10-2007, 03:30 PM
Whats this got to do with sanding down a perfectly good already stretched canvas?


Baron, Its bad English - a round about way of saying don't take short cuts. Canvas is cheap, cheap, cheap.

nw

nit-wit
07-10-2007, 03:33 PM
Also, if you're discarding the canvas you may want to destroy the image so some passer-by doesn't take a fancy to it and hang it in their living room. That happened to someone on here once.

That's happened to me before - I stuffed a load of my old drawings in the bin at college, and my fellow students fell upon them like vultures.

nw

LindaT
07-10-2007, 03:40 PM
Also be aware that oil paints become transparent with time. You may think you've painted over it opaquely but years down the road a "ghost" image may appear. You sometimes see this on the old masters, where they have changed a composition.

I have changed some elements of a painting a year later. I read some technical advice once to rub down the surface with lacquer thinner first before painting on old paint. It softens it up and gives some tack, making the new layer adhere better.

donn_granros
07-10-2007, 04:18 PM
This is a 30 x 40" I painted over an old canvas. Turned out pretty well. I fine sanded the surface, wiped in down with turpentine and it worked out well. One caveat, the new painting was painted thinly in layers and in terms of methodolgy matched the characteristics of the underpainting which was also painted quite thinly. Additionally the old painting was about 20 years old.

It's not all about cost, a previously painted surface can be nice to work on if prepared properly.

nit-wit
07-11-2007, 03:55 AM
It's not all about cost, a previously painted surface can be nice to work on if prepared properly.


True enough. Possibly? X-rays reveal many old masters have overpainted earlier works, succesfully. But that doesn't mean they didn't do it for economic reasons, or just from sheer laziness, or for fraudulent reasons (passing off old stock for new). And it doesn't mean that many paintings haven't disintegrated because of this.

I would still advocate buying a new canvas. If you like the experience of painting over old paintings, then prepare your new support to give you that experience.

There's nothing more disheartening than having a good painting flake away, from an earlier one below. It happens! It's happened to me. I'm probably not the only one! Do you want to risk it?

Best wishes,

nw

janeTuesday
07-11-2007, 07:52 AM
Well I don't know about you RTO, but I have certainly learnt a few things from what people are saying! I watched a teacher shave away little lines/layers and he made it look very easy and when I tried it I totally balls'd it up and made it look worse than before. I think unless it is a peculiar size or the painting you are about to paint over the top is more for experimentation, then just by new canvas. I have about 10 old canvas's lying around and I really think I should just put a knife through them and toss them. They are not worth the dust they collect. And there is nothing like a fresh canvas!!!

jueeab
07-11-2007, 11:26 PM
but there's the texture and strokes from the previous painting and i'd like to somehow get rid of those marks and smooth the surface out before painting over it. any solutions to this?


[scraping it off with palate knife has always worked for me]

txrembrandt
07-12-2007, 10:56 AM
The only thing I know to do is get after it with sand paper. Thats why I like acrlics.....you can gesso right over it and start anew.

Tripod
07-12-2007, 11:30 AM
I have done this several times and prefer the old marks, but of course it depends on the subject, for instance trying to create delicate skin tones on top of an old railway.