What is the best dpi for A3 output?

[nebulaoperator]

Hi everyone,
(a bit urgently)

I have A3 size poster made for a client which will go for print.
Image is way bigger then A3 so I will have to resize it to A3.
How much of bleed should I leave and what is the ultimate dpi for this kind of print? Also printer asked for a tiff file. I have flattened tiff image as it was a size of nearly 2GB. Anything else you would suggest me how to prepare the file?
Thank you in advance

[John Wheeler]

Hi nebula

No one has jumped in and I am not the expert. Most of these questions should come directly from the printer (website or phonecall). Some of this you probably already know.

- RGB vs CMYK
- In which color space or ICC profile are they expecting the image? Convert to that color space before saving file. I would attach ICC profile unless printing company specifically does not want it attached
- 8 bit vs 16 bit output (almost all as I recall are 8 bit yet some accommodate 16 bit)
- Bleed is specific to the printing company. Common is 2mm to 5mm
- You made no mention of the number of pixels per edge of your existing image. I would not know if you would need to resize up or down both because of that and also you are asking which dpi to use. Again, the printing company can tell you what is ideal for their equipment. From a viewing standpoint at 25cm distance the average eye can distinguish 5lp/mm (line pairs per mm). This translates to 254 dpi so the range of 240 to 300 dpi is excellent. Most don't view such size posters at that distance. If viewing distance increases proportionally to paper size (1.4X) then the needed dpi could be reduced by the same amount for a range between 170 and 212 dpi.
- For resizing I have had good luck with just using Image Resize in Photoshop (some swear by Perfect Resize 7 by onOne Software). Use the recommended re-sampling algorithm as suggested in the Image Resize dropdown. Also, view the image at 100% to look for resizing artifacts
- I would also suggest Proofing the image in Photoshop using the ICC profile/color space with which you will be outputting the file. This helps reduce surprises on how it will look when printed. Ideally you could try a test print with the printer (portion of image or smaller size).

Again, I am not the expert so maybe other forum members will add a post.

[nebulaoperator]

hi John,

Thanks for reply. I know I'll have to scroll a lot if you reply

This will be sRGB
I have attached ICC profile
8bit
I've red it is 3mm in UK. but as you say depending on the company is valid point.
I will have to resize it as the existing pixels are 7530 x 11464 when resized using resample option it drops down to around 3542 x 5350 pixels.

I just realise from your post that this is me and printer communication too. It is my first time when I do post for that reason I obviously noob how the whole procedure works.
Someone has mentioned that I should talk to printer directly this would also eliminate unnecessary hassle though.
Have you ever heard of any kind of bleed in the shadow area when A3 printed due 300dpi set. ( I found a post on flickr )

Many thanks Tomas

[Chain]

John covered everything I can think of!

3 mm bleed, 300 ppi, would be common settings for print and I would use this as a starting point unless you get anything else specified from the printer.

[nebulaoperator]

Originally Posted by Chain

John covered everything I can think of!

3 mm bleed, 300 ppi, would be common settings for print and I would use this as a starting point unless you get anything else specified from the printer.

Hi Chain,

Thanks for jumping in. Talking about bleed would it be reasonable to have bleed of its own photo rather then white. Thanks Tomas

[Chain]

Yes, the image should extend all the way into the bleed. If there was nothing in the bleed (white) it would be pointless.

The "bleed" area will be printed, but cropped off when they cut the paper. It is there so that when they crop it slightly inaccurate (off by 1 mm, roateted slightly, etc.) you won't get an ungly white border on your print.

[nebulaoperator]

Thank you Chain,

Clear as crystal.

[John Wheeler]

Originally Posted by nebulaoperator

hi John, Thanks for reply. I know I'll have to scroll a lot if you reply

Well Tomas, if you are implying that I am bombastic, circumlocutory, diffuse, flowery, full of air, fustian, gabby, garrulous, grandiloquent, involved, loquacious, magniloquent, palaverous, periphrastic, pleonastic, prolix, redundant, repeating, repetitious, repetitive, rhetorical, talkative, talky, tautological, tautologous, tedious, tortuous, windy, yacking you are probably right. Except for the "full of air" part. More accurately that would be "full of hot air"

Sounds like Chain has you covered. I am less than a noob on the bleed specifications yet wanted to through in a couple tidbits to make sure we are on the same page based on a comment you made about shadow area. My understanding of the bleed specifications is to make sure in a print that once "cut" there are no undesired white boundary edges. I thought the extra print size needed on the edges (the bleed spec) was mostly to accommodate the inaccuracies of the print and cut process and making sure that you don't end up with any white framing. (see http://en.wikipedia.org/wiki/Bleed_%28printing%29) While there is some actual "bleed" of ink on the paper that may help reduce the amount "bleed area" that is needed, the printing service knows what is needed for both. In the past (maybe today as well) I know there was high sensitivity and concern of too much bleed area since this would waste ink and paper and in some cases would bump you up to a larger size printing plate and or paper size (read higher cost). Again, the printing service can advice about any such concerns for their equipment. Someone in PrePress would be much better qualified to comment on this.

On another angle though, here is a link to a description of the printing origins of the term "Full Bleed." It had nothing to do with ink bleeding on the paper so was a fun read. I must admit I have not confirmed the accuracy of this article.:
http://www.mediapost.com/publications/article/93684/full-bleed.html

So I hoped you enjoyed the extra info and I at least hope that this post removes all aspersions and doubt about my verbosity

[Tony W]

Talk about bleeding edge

John you have caused me some work as I am going to have to look up some of the words in your first paragraph

[John Wheeler]

Originally Posted by Tony W

John you have caused me some work as I am going to have to look up some of the words in your first paragraph

Let me know what you find out, I just cut and paste some online synonyms. On second thought......... don't let me know

[nebulaoperator]

@ John

This kind of note regarding ,,scroll, is a very friendly gesture and suggestion that you take your own time and effort in helping other people. In this case me. So big thumbs and thank you's
I just have been introduce to full bleed. Step by step I am getting there.
How did you find this story? google suppose
By the way I have to ask same question my client asked me gloss or matt? What does your opinion and experience tell so far?

[John Wheeler]

Your welcome Tomas
I found that article with internet searches when I was trying to understand the terminology aka "Full Bleed." After bypassing all articles about "blood letting" that one happened to pop up (as I recall)

As far as Matte vs Glossy that is a good question. I always go back to what the customer wants after they know what options can be supplied (Not sure what paper options your printer can provide as there are lots of types of Photo paper depending on what type of equipment your print service is using and stocks).

If the customer really doesn't know that is harder. I have no context to advise you. When I think of poster, I think in terms of volumes of prints. If this is just a single larger print then that is different. I would take into account where the image is going to be displayed and the feel you want. Glossy ends up being a little more saturated with a sharper feel yet you get killed by reflections (depends on environment). I think that is one of the reasons many opt for Lustre prints. Just some quick thoughts and I am sure there are others that could advise better than I.

[nebulaoperator]

John,

,,Glossy ends up being a little more saturated with a sharper feel yet you get killed by reflections (depends on environment). I think that is one of the reasons many opt for Lustre prints. Just some quick thoughts and I am sure there are others that could advise better than I.,, Very helpful as some things have to be taken in consideration about light in the space, reflection factor and other tiny bitty things.
I think I will go into clients apartment to and we both look for the space to hang it.
Seems that story becomes kind of tautological but in a good sense :
http://thebutcherblog.com/full-bleed/
Edit: Sounds like it is the origin

[Tony W]

The discussion Matt, Lustre or Glossy is an interesting one and I think the obvious answer is that glossy appears sharper than matt can be misleading in terms of inkjet prints at least.

The criteria for sharpness seemed to generally hold true for analogue prints on fibre based paper, however I believe that other factors effect inkjet printing not least of which is the way that the paper absorbs ink or the way that the ink sits on the surface. I believe although not experienced first hand that it is possible that due to these factors some glossy papers can appear less sharp than the manufacturers Mat paper stock.

If the print is going to be mounted behind glass then the choice of glossy vs matt may be irrelevant particularly if NR glass is going to be used. If not mounted behind glass or protected in any other way then perhaps Mat or Lustre should be considered as it is likely that it will not show dust and finger marks as readily as gloss stock.

I would also suggest that proper preparation for the media needs to be considered relating to sharpening. My guess here is that Matt paper may in some cases need slightly more sharpening for output than either glossy or lustre which will only be known once samples have been acquired on both types

[nebulaoperator]

@tony
Very valuable advise from you about sharpness. I suspect there will bematte. What is NR glass by the way? Thanks Tony

[Tony W]

Sorry about the abbreviation, I was referring to Non Reflective glass or to use another name Anti Reflective glass.

[nebulaoperator]

@Tony
Not a problem What other papers to be printed on apart from fibre?

[Tony W]

Fibre based or Baryta papers for inkjets try to give the feel of traditional analogue darkroom prints. There are so many other types of papers varying between manufacturers that the choices can be confusing.

As I believe you are sending your prints out then it is likely that your lab will have a limited selection of paper types. These should have been chosen to match their printers characteristics and allow them to produce the best results. Hopefully your printers will be able to either give you or show you samples of the paper surface and weight of the paper.

Weight and feel are likely to have less importance to you or the client if they are to be mounted and matted and under glass frame. What maybe of more importance is how they show the delicate highlights and shadow seperation in your images as even under glass this will be noticeable. A good printer will know this and be perhaps in a better situation to advise you of your choices by demonstrating the differences.

[nebulaoperator]

@tony
Hi, I am late with my reply. So much to do and so little time. paper was chosen matte. I have to say shadows and highlights were very subtle and the gradients were clear and smooth to recognise. Printers were very helpful and demonstrating a professional knowledge from the start till the end. They even asked about the house, height of the ceiling and etc just t ogive the best possible advise. They simply cared about it. I had privilege to see my work hanged on the wall framed and under glass.We both client and me were very satisfied

Thanks Tony.

[Tony W]

Great result and pleased that you have found a knowledgeable printer that cares about their work

[nebulaoperator]

I also found people here that cares. Thank you.