Image area get stain

[saravinfo10]

Why image area get stain like this in web offset

 

[gordo]

Why image area get stain like this in web offset

Could you post a PDF/image of the file so that we can see what you were supposed to print?

 

[saravinfo10]

View attachment pdf

 

[bill kahny]

post the electronic file not a picture of you press sheet I think its just offset.

 

[saravinfo10]

Yes it's offset sheet electronic file not available. In sheet why the image area get stain. If desensitizing agent not applied on
will image and non image area get stain. But here image area only get stain Why?

 

[Alois Senefelder]

Saravinfo 10


Answers - 1) Badly Developed Plate

2) Plate NOT Gummed correctly



Regards, Alois

 

[dabob]

Looks like scumming to me . . . dampener issues, emulsification . . .??????

 

[saravinfo10]

If gum not applied will image area will pick stain as in the pic.

 

[saravinfo10]

What is my doubt is if gum not applied will image area get stain during printing

 

[gordo]

If gum not applied will image area will pick stain as in the pic.

Yes.

 

[saravinfo10]

We are applying gum to protect the non image area and to give hydrophilic property to the non image area then why image area which has photosensitive coating get stain. Image area must get ink only not stain.

 

[turbotom1052]

are you referring to the stain surrounding the black type? If so I would suggest a brisk circular motion cleaning of the plate AFTER youve removed the ink with a solvent. One you've thoroughly cleaned the black plate with a creme style plate cleaner suitable for your brand of plates I would apply a generous coating of AGE and then be sure to buff out the AGE completely leaving no traces of the AGE.

 

[saravinfo10]

My question is while making plates we are applying gum to the plate then send to the press room. If we did not apply gum in the plate making stain will gum in the press run. But you see in the pic black type and yellow screen are got stain those are image area. If gum not applied in plate making non image area only will get stain. But in this plate image area like black and yellow screean re got stain because not applying of gum in plate making. My question is we are applying gum to the plate to protect the non image area. why image also got stai

 

[Alois Senefelder]

saravinfo10,


Question: Are these "Stains" visible on the plate - BEFORE the plate image areas are inked - in, via the Press. ?


1) Whose Plates are you using? 2) Are you using a Plate Exposure Control Strip?




Regards, Alois

 

[saravinfo10]

No the stains are visible after inking

 

[Alois Senefelder]

saravinfo10,



Let us be CLEAR - the stains appear on the paper and plate after inking - up?


Answer questions - 1) and 2) please.


3) Have you checked the Chemistry and Conductivity of the Plate Developer/Gum or Finisher?


Regards, Alois

 

[saravinfo10]

Yes the stain appear on the plate and paper after inking up.
1.we are using topaz ps plate
2. Not used the control strip
3.chemistry and conductivity of developer,finisher or checked
they are ok

 

[Alois Senefelder]

saravinfo10,


SO every plate on every unit of the press - HAS these "Stains/Oxidation Marks" somewhere randomly?


Regards, Alois

 

[saravinfo10]

Yes every plate on every unit of the press has these stains /oxidation marks.