Paper Thickness

[Manfred M]

Allan,

Thanks for the information, I'll check it out.

Carefully said, the slower print speed setting gives you uni-directional printing; i.e. the printer only prints with the print head moving in one direction rather than printing in both directions. There are some theoretical advantages of doing so, but in practice I have not been able to detect any discernible print quality differences, even under magnification.

[Shadowman]

Carefully said, the slower print speed setting gives you uni-directional printing; i.e. the printer only prints with the print head moving in one direction rather than printing in both directions. There are some theoretical advantages of doing so, but in practice I have not been able to detect any discernible print quality differences, even under magnification.

Manfred,

Did a few prints today using the thin Matte paper and skintones look good from a distance, I placed the print on a lightpad and the paper's fibers were clearly visible. I might try a thicker paper in the future.

[rudi]

.... for specific presentations though.

Hi John,
I do not know exactly what you by 'presentations', but a few years ago we did some prints on http://www.bonjetmedia.com/en/bonjet...f180-bj4mbf200, a front print/Backlit display film.
They do not produce 59 cm rolls anymore. Canon has 61 cm rolls frontprint/backlit display film available, but not yet used till now.

[Shadowman]

Hi John,
I do not know exactly what you by 'presentations', but a few years ago we did some prints on http://www.bonjetmedia.com/en/bonjet...f180-bj4mbf200, a front print/Backlit display film.
They do not produce 59 cm rolls anymore. Canon has 61 cm rolls frontprint/backlit display film available, but not yet used till now.

Rudi,

I was referring to presentations such as in the link, however I've found that the thin paper I was using would not be suitable; plus did some reading on matte papers and found a comment about yellowing because of the strong brighteners used. However, as most presentations are temporary the yellowing might not be an issue, the visible fibers showing the paper could be an issue and controlling the viewers distance from the image will be necessary. Thanks for the link, I do have a packet of backlight film from Inkpress media that I'll try out once I get a suitable image to print.

www.40visuals.com/

[Manfred M]

John - the use of fibres is part and parcel of the paper-making process and the longer the fibre, the stiffer the paper. This is something that we want in a photo paper, so this problem you are seeing is to be expected. Any non-woven product like paper will have them. Short fibres are associated with softer papers; toilet paper and paper tissues are typical examples of short fibre paper and these types of paper are going to show less individual fibres, but will also be very flexible and are totally unsuitable for printing.

The yellowing is primarily due to the breakdown of the Optical Brightening Agents (OBA) used in many papers to make them look whiter. They do break down over time when exposed to UV, heat and chemical contaminants in the air. If you are using a cold light source, I suspect this will be less of a problem, but any light source that generates heat is not going to be all that kind. For higher end photo papers, especially from main stream sources, you should be able to determine if they contain an OBA. Paper descriptions that contain "bright" or "vivid" should be avoided. The main issue with OBAs fading is that they often do so unevenly. The yellowness of paper is a natural property of any paper (versus say the white we get on a computer screen).

Thicker papers are going to also have fibres and will block more light, so that means the lightbox will require a move powerful light source, which in turn could generate more heat.

Clear resins are going to be fibre free and I have certainly used these in the past, but as mentioned in #18, they require a translucent diffuser. Some more bad news. All resins yellow over time, especially in the presence of UV light sources. Some are UV stabilized, but that only delays the onset. Opal glass does not yellow.

[Shadowman]

John - the use of fibres is part and parcel of the paper-making process and the longer the fibre, the stiffer the paper. This is something that we want in a photo paper, so this problem you are seeing is to be expected. Any non-woven product like paper will have them. Short fibres are associated with softer papers; toilet paper and paper tissues are typical examples of short fibre paper and these types of paper are going to show less individual fibres, but will also be very flexible and are totally unsuitable for printing.

The yellowing is primarily due to the breakdown of the Optical Brightening Agents (OBA) used in many papers to make them look whiter. They do break down over time when exposed to UV, heat and chemical contaminants in the air. If you are using a cold light source, I suspect this will be less of a problem, but any light source that generates heat is not going to be all that kind. For higher end photo papers, especially from main stream sources, you should be able to determine if they contain an OBA. Paper descriptions that contain "bright" or "vivid" should be avoided. The main issue with OBAs fading is that they often do so unevenly. The yellowness of paper is a natural property of any paper (versus say the white we get on a computer screen).

Thicker papers are going to also have fibres and will block more light, so that means the lightbox will require a move powerful light source, which in turn could generate more heat.

Clear resins are going to be fibre free and I have certainly used these in the past, but as mentioned in #18, they require a translucent diffuser. Some more bad news. All resins yellow over time, especially in the presence of UV light sources. Some are UV stabilized, but that only delays the onset. Opal glass does not yellow.

Manfred,

Thanks for the information on papers; especially on the OBAs and environmental effects on papers. For the lighting I purchased an LED pad that is typically used for sketching, I thought it might be useful for viewing images on backlit film.

[Polar01]

John just off topic kind of, does you P5000 come able to use rolls?

Cheers: Allan

[Shadowman]

John just off topic kind of, does you P5000 come able to use rolls?

Cheers: Allan

Allan,

Yes it does, not as thrilled with it as I thought I'd be; issue is paper curl after printing. I have a habit of placing a clean sheet over black and white images and I can apply a weight but it takes time to remove the curl. I saw a YouTube tip where they use a roller to give the image a twist in the opposite direction but that seems like it will damage or mar the surface. I could always mount the print after it dries to give it a natural formation.

[Manfred M]

I saw a YouTube tip where they use a roller to give the image a twist in the opposite direction but that seems like it will damage or mar the surface.

John - that roller based technology is built into commercial paper (and metal) handling equipment and has been in use for decades to remove curl from roll stock. It does not damage the surface or the print so long as any friction that can cause abrasion is minimized. The weight / pressing technique does not work particularly well.

[DigitalScape]

Don't know how North American paper weight calculations convert to European/Australiasia calculations, but of my main papers, Matte is 285 gsm and Mono Gloss is 320 gsm.

I found this conversion:
1 Pounds (lbs), = 1.4802 Grams Per Square Meter (GSM).
1 Grams Per Square Meter (GSM), = 0.6756 Pounds (lbs)

[Manfred M]

I found this conversion:
1 Pounds (lbs), = 1.4802 Grams Per Square Meter (GSM).
1 Grams Per Square Meter (GSM), = 0.6756 Pounds (lbs)

Sorry, that makes no sense at all. There has to be an underlying assumption on the thickness of the paper for this to work. Given the same base, if you double the thickness of the paper, it would have twice the number of grams / sq meter.

Some real spec numbers; Epson Legacy Fiber paper which is 19 mils is 314 grams / sq meter.

Epson Premium Luster (a resin coated paper) is 10 mils thick and is 240 grams / sq meter.

[Shadowman]

John - that roller based technology is built into commercial paper (and metal) handling equipment and has been in use for decades to remove curl from roll stock. It does not damage the surface or the print so long as any friction that can cause abrasion is minimized. The weight / pressing technique does not work particularly well.

Manfred,

Found a link describing just what you stated.
http://www.redrivercatalog.com/infoc...per-rolls.html

[Manfred M]

Manfred,

Found a link describing just what you stated.

You have shown a manual flattener. The ones I am referring to are a multiple roller that is built into the machine paper handling mechanism. You can see the multiple rolls near the output of the machines as well as the large roll of paper being fed into the machine.

http://www.footprintsequipment.com/i...lus131Plus.pdf

[DanK]

Sorry, that makes no sense at all. There has to be an underlying assumption on the thickness of the paper for this to work. Given the same base, if you double the thickness of the paper, it would have twice the number of grams / sq meter.

Some real spec numbers; Epson Legacy Fiber paper which is 19 mils is 314 grams / sq meter.

Epson Premium Luster (a resin coated paper) is 10 mils thick and is 240 grams / sq meter.

It's a standard conversion. What is missing is not thickness, which would cancel out in the conversion from one metric to another: the paper sample is staying the same, but a different scale is being used. However, on the non-metric side, what is missing is the surface area in the denominator: pounds per square WHAT? With a little arithmetic, one could find this, but I never see it mentioned. In nonmetric terms, papers are labeled simply in terms of "pounds" (although I think there are two scales, one for text and one for covers), and in every place I have found it, the conversion is to gsm, which of course specifies the denominator.

[Manfred M]

It's a standard conversion. What is missing is not thickness, which would cancel out in the conversion from one metric to another: the paper sample is staying the same, but a different scale is being used. However, on the non-metric side, what is missing is the surface area in the denominator: pounds per square WHAT? With a little arithmetic, one could find this, but I never see it mentioned. In nonmetric terms, papers are labeled simply in terms of "pounds" (although I think there are two scales, one for text and one for covers), and in every place I have found it, the conversion is to gsm, which of course specifies the denominator.

Dan - paper in pounds is the weight of a ream of paper. A ream is 500 sheets (all sheets being identical in dimension). If you have 20 lb paper, then a ream of it weighs 20 lbs.

[Polar01]

I think that getting into weight is not really a place to go if you have little to no understanding of paper. Case in point 500 sheets of 8.5" x 11" weights 5lbs however it is referenced to as 20lb paper. The weight of the Bond paper is based on a ream being 500 sheets and sheet size of 22" x 17" which weighs 20lbs. If you go to offset paper weight is based on a ream of 500 sheets of a size of 25" x 38". Now with in bond paper you could have 15lb, 17lb, 20lb, 24lb papers and offset 40lb, 50lb and 60lb being the most common.

Cheers: Allan

[DanK]

Allan,

Beat me to it. I looked up the Imperial (?) paper weight standards after Manfred's post. It's like so much of the non-metric system: needlessly complicated. No wonder that every country in the world other than the US and Myanmar has gone metric.

However, stripped of all the gratuitous complexity--such as having several different paper sizes used to define paper weight--the principle is the same: paper weight is expressed as units weight per unit surface area. In the nonmetric system, the denominator isn't given; you would have to know or look up the sheet dimensions for the particular type of paper used in the definition and then multiply the surface area of one sheet by 500. In the metric system, the measure tells you both: the weight is the number of grams per square meter. Thickness is correlated with paper weight, of course, but it isn't the defining characteristic.

you wrote:

I think that getting into weight is not really a place to go if you have little to no understanding of paper.

I disagree. understanding paper weight is important for printing. Just avoid non-metric measures, and it is simple. All of the paper manufacturers I have purchased from use the metric gsm scale, and the printer instructions I have read have also all used that scale. Stick with that, and it is not complicated. For example, my Canon printer instructions say that one can use the main feed up to a certain weight, expressed in gsm, and above that, one should use the manual feed.

[Polar01]

Dan I have to disagree with your disagree, case in point, printing a job on 60lb offset paper which as a standard thickness of "A", now to get the printed block into the case (cover) it is too thick to pass through the binder. Now I use the same 60lb offset stock however I get it milled to a thickness of "D" which is the standard thickness of 45lb offset it fits in the case and passes through the binder coming out as a finished book. Now both stocks are 60lb but much different in thickness per sheet.
Now the ICC information that is supplied by the paper manufacture is very important as it also gives thickness, I had make a grid of stocks I used with that information on it. To me I could care less about the g/m2 it was the thickness that I got off the data sheets that gave me the info I need to print on my Epson 4900.

Cheers: Allan