Need help diagnosing problem with colour paper negative

[mkillmer]

I've been developing colur paper negatives with fairly good results, however I seem to be running into a problem with the latest images I've developed. There is a blue gradient that goes across the entire paper.
This is not related to the image (the blue extends into the area covered by the sheet film holder).
I am using the Tetenal RA-4 kit. The process I use is:
Heat chems to 35 degrees in Jobo bath
Dev for 45 secs
Stop for 30
blix for 45 secs
wash

Pictures I took last night are fine. Pictures I took today all have the blue on them.
Last time I had this, I dumped the developer and the blix. But this developer is only a few days old, so I dont want to dump it.
I read somewhere, that the blue means the blix is dead, so ive tried a longer blix (2 min) but that did not work.
Any ideas?
Thanks in advance
Mark

 

[markbarendt]

I've had similar problems, both JOBO and tray.

I added two 30-second rinses, one before the developer, one before the blix. I also keep the working chemicals in separate bottles from stock solutions.

 

[Mike Wilde]

yes, blue balcks usually means weak blix. As Mark said. Kepp dev and blix bottles sepaprate at all times, and don't let any blix contaminate dev. Even at trace amounts wiredness happens tothe print. Sorry, more detailed notes on the effects are not at hand where I type this.

 

[mkillmer]

Thanks for the responses.
If I understand, then you suggest that my developer may be contaminated? How would I test that?

I guess I could develop a peice of unexposed paper and look at it before blixing? What should I see?
The problem that I foresee is that the paper I use (Fuji crystal archive) has a blue coating, I guess this will be there until I blix? So maybe this would not work?
Any ideas are really welcome!!

 

[markbarendt]

I'm saying the blix may be contaminated.

The rinse before the blix protects the blix. The rinse before the developer protects the developer.

 

[mkillmer]

Hi Mark,
Thanks for clarifying. I'll take your advice and separate out, say, 200ml for my working solution and use that until it is exhausted or contaminated. Combined with the extra washes, I'm hoping to minimise the impact of this issue.
Thanks for the advice.
Mark

 

[markbarendt]

I easily get 10-15 8x10's with Kodak chems that way, Tetenol should get about the same.

 

[mkillmer]

I dumped my chemicals and restarted - oh no... Still blue gradients!!!
So I got to thinking... and developed an unexposed piece of paper - white.
The problem is in the camera, not the chems!!
I dont know what yet - but I just to another colour paper negative - this time with a black sheet over the back of the camera - Success.
I must have some sort of light leak that reflects off a certain colour?
Investigating...