Dark vertical lines on printed photo

[George222]

Hi,

I am relatively new with lightroom, and have an issue.

I imported a Canon Raw image, applied a Black Mamba downloaded preset, basically to make it black and white, and exported as full sized JPEG at 300dpi.

I then took it to the printing service, and asked them to print a 40x60 photo.
After printing, they show me these black vertical lines all over my photo (which is not visible neither on mine, nor on their monitors).

Im attaching both a compressed JPEG and a photo of the print.
Please could you help me out on this, thanks.

 

[Jim Wilde]

Hi, welcome to the forum.

A couple of questions: 40x60 what? Inches, Centimetres?
What are the pixel dimensions of the raw image that you exported? What export settings did you use, particularly the quality setting in the File Settings box, and then what were the exact settings in the Image Quality box, i.e. did you resize (if so to what?), was "Don't Enlarge" checked, what measurement did you use (Pixels, In or Cm)?

If you can get back to us on those questions we'll try to help figure out what's going on.

 

[George222]

Hi, welcome to the forum.

A couple of questions: 40x60 what? Inches, Centimetres?
What are the pixel dimensions of the raw image that you exported? What export settings did you use, particularly the quality setting in the File Settings box, and then what were the exact settings in the Image Quality box, i.e. did you resize (if so to what?), was "Don't Enlarge" checked, what measurement did you use (Pixels, In or Cm)?

If you can get back to us on those questions we'll try to help figure out what's going on.

Hi, thank you for your reply.

1- 40x60 are centimeters.

2- the pixel dimensions of the image are: 3780 × 2520, in sRGB IEC61966-2.1

3- My export process was : Burn full sized JPGs preset, Quality 100%, No resizing, measuremens were 300 pixels per inch.


Might there be something wrong with the print services printer? or is something wrong on my side?

Thanks

 

[Tony Jay]

That kind of banding could well be due to blocked nozzles on a printer.
But more investigation is required because, usually, the printers in a printing service are used so frequently that blocked nozzles are very rare.
In that respect knowing exactly what type and model of printer was used would also be helpful.

What would be helpful is a screenshot of the original image in Lightroom at 1:1 with the area where the banding is occurring being shown.
That way possibilities such as pattern noise (unlikely I know) could be excluded.

The bottom line is that either this pattern is actually present in the image itself or it is a printer artefact.

Tony Jay

 

[Jim Wilde]

OK, the first observation is that you really haven't got enough pixels in your image to print 60x40cm at 300ppi.

Let's do the maths: converting from cm to inches you're wanting a 23.6" x 15.7" print, and you wanted it printed at 300ppi....which means your image needs to be 7080 x 4710 px, which is roughly 4 times the size of what you have. So to get that resolution from your source image means that it has to be significantly upsized, which you can either do in Lightroom or your print service can do it. It appears that you didn't, so I guess your printer did (assuming he didn't print at a lower dpi setting) so maybe that upsizing has caused the artefacts.

Unfortunately, I'm not an expert in this area, so we'll have to wait for one of our other members to chime in (which I see Tony has just done).