Kodak violet news gold plate

[printryt]

I need help from KODAK Violet News Gold Plate users...... and mako ctp users....


i am using mako 8 CTP machine and using Kodak for my plates..

i am experiencing dot loss in my plates. i am getting around 5-7% dot loss after being used by the press.

1. is the plate sensitive to press chemicals?
2. should i check the exposure/laser setting in my ctp machine (57%)? the machine is brand new
3. any reccomendations that you could give me?


Thank you very much

 

[maxon]

Of course you need to recalibrate the laser output, as the Gold version plates are slightly less sensitive 50 microjoules/sqm compared to 35-ish for Violetprint. Use a Stouffer or UGRA as usual.
Do you use the same Kodak 500 violet developer as before or did you switch to the recommended Kodak 206 chemistry ? The Gold is a very low chemistry plate when used with 206 developer. Once you switch to Kodak 206 you cannot process standard Violetprint or Violetnews plates anymore.

 

[maxon]

My bad, I meant ujoules/sq.cm

 

[printryt]

thank you..

yes.. i am still using kodak 500 for the developer and kodak 500r for the replenisher... our supplier here does not carry that chemistyry yet... are you suggesting that i use kodak 206 chemistry?

 

[maxon]

By all means, considering the very low replenishment and antiox rates and doubling the developer life. It's also a cleaner working developer, just rinse the machine almost without any scrubbing. When switching to 206 be careful to clean the machine very carefully, should probably take a whole day to take out all old polymer deposits, take out the pipe work towards the circulation pump etc.

 

[printryt]

ok. i'll consider changing the chemical right away. my supply depends on my supplier if they have that item available.


Thank you very much.

 

[printryt]

one more thing... does the chemical 500/206 have any effect on the image on the plate (dot loss/gain/etc)

 

[maxon]

In theory, yes you can loose highlight dot if the developer is much too aggresive i.e. developer temperature way out of specification or incorrect processing speed. Recheck your machine settings according to Kodak specifications. But this is not the case here, you simply experienced dot loss because of incorrect laser exposure, this is the number one reason in 99 percent of all cases.
Image wear may also be caused by a number of factors like press conditions, violet plates should hold for more than 200000 impressions unbaked. The coating is strong and quite tolerant to various fountain solutions, chemicals and inks, but I've seen a lot of silly mistakes over the years, like pressmen cleaning the plate with blanket cleaner because they didn't have anything else at hand etc.

Where are you located ? What processor do you use ? PM me.

 

[Jim Klann]

While we are on the subject

While we are on the subject

I've got a Dimension 412 that I've been running Azura plates in and doing OK. But Agfa has replaced the plate with the Azura TS.

I'm having problems with the TS plates holding the dot below 2% and overall I'm muddy. I've tried lowering the laser powers but I can't seem to get rid of the banding.

Could it be that the laser's are so low that they are hard to control ? When I run the tint balance I either get mid-tone banding or shadow banding !

Any suggestions ?

Thanks in advance for any help.

 

[JohnW@Kodak]

Hi printryt,
have you asked your supplier for any Kodak assistance?
If you need any further support please send me an e mail with your company name and address so I can direct your questions to the appropriate Kodak regional technical support.
Regards
John

 

[printryt]

Good day,

i got assisstance form our local kodak supplier. we tried to adjust the laser power (exposure) and right now we are still monitoring every plate output. our recent plate got a satisfactory result before the press. but after using it in the press, the screens in the color bars lost from 5-13%. do you have any idea on what is happening? is kodak violet news gold digital plates very sensitive to other press chemicals?

 

[JohnW@Kodak]

Hi printryt,
the Violet News Gold plate has good overall chemical resistance but as with all products there could be a chemical which may affect the plate. You could try a drop test of the chemicals you use on a solid and halftone area to see if this has any affect.
If the dot sharpening is happening on make ready then it points probably to something in pre press, but if sharpening at end of a long run then press conditions and chemicals could be a factor.
I presume the room opertaing conditions are within specification for temperature and Humidity as this can also have an affect along with processor setting in pre heat etc, but guess these have been checked by your suppliers technical support?
You could also check the developer brushes for settings, wear etc.
These questions are always difficult to evaluate from a distance and would recommend you work with the supplier who should be in dialogue with Kodak technical support people.
Regards
John

 

[printryt]

Thanks John,


I monitor the Humidity and Temperature. I am whithin the range.
I'll be checking press chemicals.

Mark

 

[printryt]

Good Day,

Hi again maxon, i was able to calibrate the laser exposure FROM 57% (52% reading on the 50% screen) TO 65% (55% reading on the 50% screen) . This value is according to our local supplier of kodak plate, that the reading in the 50% screen should have a range of 54% - 56% values. by the way we are now using T85N.

The problem is still present, dot loss of 5-9%. we checked our press chemicals here and it passed the drop test.

Do you have any more suggestion, well obviously our supplier and us are having a hard time figuring out the solution for our problem. We would appreciate all the help we can get from your replies.


Is the laser exposure correct?
or do we need to increase it again so we can obtain a much stronger image (image & screen) in the plate?




Thank You again.
Mark Ignacio

 

[maxon]

Hello Mark,
Again, the one and only procedure to correctly set up the laser intensity is by using a UGRA plate wedge or a Stouffer, and run the step wedge test pattern procedure as described by ECRM in their Mako 8 operator manual - document AG114123, page 23 onwards, it's the printed manual you got with the platesetter, also described by Kodak in their documentation.
Do not evaluate the exposure intensity based on dot gain prediction in uncalibrated mode, you are just wasting time.
If you don't have a step wedge at hand, borrow one, or ask your plate supplier to give you.

 

[printryt]

Hello again,


My supplier did the stouffer test today. and it turned out that STEP 4 almost vanishes when rubbed with developer.

So we did apply the computation.. it turned out that from 65 we should use 105 exposure value.

I just want to confirm if we should have the "tail" (light/midtones) at STEP 4 because from what I read the tail should be at STEP 5-6...

please give insights.


Thank You again

 

[maxon]

You have PM

 

[JohnW@Kodak]

Hi printryt
When using the Kodak 500 developer our technical people state that the Stouffer step wedge reading should be a solid step 3 and a clear step in 5 to 6 ( no coating). Using an Ugra wedge it would be one step lower ie solid step 2 clear step 4 to 5.
You should not rub the wedge with developer as this will always affect the wedge as it is effectively over developing the plate.
If you want to try rubbing back the wedge then you should only use water, but that should only affect the tail of the wedge slightly and is not an indication of imaging sharpening.
As stated before if processor developer brushes are worn then this could give an issue of under development and a fringe on the dots which will sharpen during the press run.
The other area could be platesetter flare and or dirty optics which can give a fringe on the dots as well.
Regards
John

 

[JohnW@Kodak]

Hi printryt,
Apologies in advance as I may have confused you- I must be having a bad day?
The figures I gave you for the step wedge were for Violet Print plate and 500 developer for the commercial printer.
The correct step wedge reading with Violet News Gold/T85 using 500 developer for newspapers is a step higher that is solid step 4 clear step 6 to 7 so from what you are telling me you have been under exposing and that the new exposure seems more like where you should be.
It is the solid step that is the most important reading and the claer step some guide as to where you are.
Regards
John

 

[printryt]

can laquer thinner affect the screen values for UV plates?