Larger render totally White :(

[cyphyr]

Ok I rendered a small high resolution test image first (that would be the first image below) at 571px x 800px Detail 0.8 AA8 GI 1/1. Looks fine. I then rendered it with exactly the same settings but larger, this time 1023px x 1432px but this time it rendered completely white. The PrePass was also very strange, very large pixels, with greenish edging (I'll try for a screen grab).
Any suggestions as to what the issue could be and more importantly what the cure is. I need to render at as high a resolution as possible as this is a job for print.
Thanks guys
Richard

[Henry Blewer]

I would almost say the second image is an alpha, but ti does not match anything in the first render. I have not had this occur. Could it be that the prepass is using data it generated on an earlier image? Try closing the render window. Then change the render settings on the render tab. This may clear buffered data.
It's probably something else entirely. I am really reaching and guessing, and the Maya have predicted this with their calendar. 

[cyphyr]

The second image is not an alpha, see the slight green luminous halo about the tree line (compare with first image) also the PrePass is completely blown out. It's opened on a fresh start up of the pc and TG2 so its not a memory buffer issue. I think it may be memory related in some way though. I'll try again at a smaller res and see if there's a cut off point.

Richard

[dandelO]

I've had these weird effects by using extreme GI combined with AA bloom, the bloom makes the GI pixels very large. I don't think this is it though, your scene doesn't appear to have very extreme GI settings.

[cyphyr]

I can be so dense some times 
One of the populations that had been located in a separate location I had moved into the project folder and I had forgotten to re-assign the paths. Only the alpha's were missing which was odd and I cant think why it would blow out the whole sky
But it works now, thanks for looking anyway

Richard

[dandelO]

[Oshyan]

If the image without alpha would make large areas of white, it could overwhelm the GI calculations and do this. I was going to say, it looks like the image has been massively overexposed...

Glad you sorted it out.

- Oshyan