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Optimal TIF file resolution for QTR?

Optimal TIF file resolution for QTR?

2017-02-27 by dtrout@...

I know from experience when using the standard Epson driver on the x900 printers that best results are obtained by NOT allowing the driver to do any resampling to the native printer input resolution when printing files, and instead you should ideally send the driver either a 360ppi file (or 720ppi if you also enable "Finest Detail" in the driver settings). Doing it this way lets you optimize any necessary resampling outside the driver and the driver will not have to do any resampling itself (which is generally not as good).

With QTR, I'd like to understand its resampling behavior. Consider the following cases:

1. Input TIF < 360ppi
2. Input TIF = 360ppi
3. 360ppi < Input TIF < 720ppi
4. Input TIF = 720ppi

I'm going to guess it is "QuadToPrinter" where any resampling would occur. In any case, how exactly does QTR behave in the four cases above on x900 printers?

Thanks, Dave


Re: Optimal TIF file resolution for QTR?

2017-02-27 by brian_downunda@...

See https://groups.yahoo.com/neo/groups/QuadtoneRIP/conversations/messages/12631

My understanding based on this is that QTR expects 720. On Windows if it receives more or less than this then QTR itself resamples to 720. On OS X this resampling is done by the OS printing pipeline. My experience on Windows is that the resampling performed by QTR is fine, although you can get slightly better results by resizing in Qimage, but you have to examine the print under a loop to see it. My understand of OS X is that the resampling performed by the printing pipeline is best avoided.

Re: [QuadtoneRIP] Re: Optimal TIF file resolution for QTR?

2017-02-27 by Roy Harrington

Thanks for the link to my previous post.

But I'm not sure of your statement "My understand of OS X is that the resampling
performed by the printing pipeline is best avoided." I've never heard of this or
seen any evidence of this.

Personally, almost all of my images work out to the 360range and I just
send it as is to QTR driver or any other driver as is (OSX). Making things exact
if you are really exact is fine but being off by a tiny bit due to roundoffs etc is
likely to be bad -- i.e. 720.03 PPI is bad and you may not know about it. Also
positioning on an exact 1/720in boundary is easy to screw up.

Roy

Show quoted textHide quoted text
On Mon, Feb 27, 2017 at 1:32 PM, brian_downunda@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:


See https://groups.yahoo.com/neo/groups/QuadtoneRIP/conversations/messages/12631

My understanding based on this is that QTR expects 720. On Windows if it receives more or less than this then QTR itself resamples to 720. On OS X this resampling is done by the OS printing pipeline. My experience on Windows is that the resampling performed by QTR is fine, although you can get slightly better results by resizing in Qimage, but you have to examine the print under a loop to see it. My understand of OS X is that the resampling performed by the printing pipeline is best avoided.




--
Roy Harrington
roy@...
www.harrington.com

Re: Optimal TIF file resolution for QTR?

2017-02-27 by dtrout@...

Thanks Brian - very helpful.

I'm a PC user of QTR (should have mentioned that in my original post). From my reading of the other thread it sounds like QTR will do the resampling on Windows. I don't want to get into the pros/cons on this topic, I just want to understand exactly what QTR does. I'll decide what to do with my files from there :-)

So for the cases I mention in the original post, I'm assuming this is the behavior on QTR on Windows:

1. Input TIF < 360ppi (QTR will upsample to 720ppi)
2. Input TIF = 360ppi (QTR will upsample to 720ppi)
3. 360ppi < Input TIF < 720ppi (QTR will upsample to 720ppi)
4. Input TIF = 720ppi (QTR will NOT resample)

Roy, can you confirm the above?

Many thanks,
Dave

Re: Optimal TIF file resolution for QTR?

2017-02-27 by brian_downunda@...

As you know, I'm not an OS X user. At one stage I did a lot of reading on other forums on the sampling and resizing issue, and there was enough mention of this by enough people who seemed to know their stuff for me to accept it as fact. Are you disagreeing with the claim of where the resampling is done in OS X, or how good it is (or both)?


---In QuadtoneRIP@yahoogroups.com, <roy@...> wrote :

Thanks for the link to my previous post.

But I'm not sure of your statement "My understand of OS X is that the resampling
performed by the printing pipeline is best avoided." I've never heard of this or
seen any evidence of this.

Re: [QuadtoneRIP] Re: Optimal TIF file resolution for QTR?

2017-02-28 by Roy Harrington

Dave,

I think its more accurate to say in (4) that QTR driver resamples to 720dpi on the correct pixel boundary.
Now, under the best conditions if you set margins appropriately that probably does't change any values.
But if you use metric or you use decimal values in margins you are likely to be doing worse.
Try it out. Make artificial test cases and see what you get. You may find it interesting -- but I don't think
it's important in real images.

Roy
Show quoted textHide quoted text
On Mon, Feb 27, 2017 at 2:47 PM, dtrout@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:


Thanks Brian - very helpful.

I'm a PC user of QTR (should have mentioned that in my original post). From my reading of the other thread it sounds like QTR will do the resampling on Windows. I don't want to get into the pros/cons on this topic, I just want to understand exactly what QTR does. I'll decide what to do with my files from there :-)

So for the cases I mention in the original post, I'm assuming this is the behavior on QTR on Windows:

1. Input TIF < 360ppi (QTR will upsample to 720ppi)
2. Input TIF = 360ppi (QTR will upsample to 720ppi)
3. 360ppi < Input TIF < 720ppi (QTR will upsample to 720ppi)
4. Input TIF = 720ppi (QTR will NOT resample)

Roy, can you confirm the above?

Many thanks,
Dave




--
Roy Harrington
roy@...
www.harrington.com

Re: [QuadtoneRIP] Re: Optimal TIF file resolution for QTR?

2017-02-28 by Roy Harrington

Brian,

Sure, resampling is done during the print process. I'm not privy to the internals of OSX but I9;d figure you
are right that its not up to say Photoshop with special algorithms. But my real point is that none of this
matters. First, because we're talking about resolutions that are too high to be visible. Second, is sort of
philosophical -- we're trying to make analog images from digital data. So the notion of "exactness" is
what we are trying to get away from. I've spent a ton of time trying to hide exactness in the print process.
The "weave" discussions are all about hiding exactness and perfect aligning of dots. The "dither" stuff is
all about making things seem random. So going out of the way to try and make exactness the goal
to me seems just in the wrong direction of what one wants.

Roy

Show quoted textHide quoted text
On Mon, Feb 27, 2017 at 3:54 PM, brian_downunda@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:


As you know, I'm not an OS X user. At one stage I did a lot of reading on other forums on the sampling and resizing issue, and there was enough mention of this by enough people who seemed to know their stuff for me to accept it as fact. Are you disagreeing with the claim of where the resampling is done in OS X, or how good it is (or both)?


---In QuadtoneRIP@yahoogroups.com, wrote :

Thanks for the link to my previous post.

But I'm not sure of your statement "My understand of OS X is that the resampling
performed by the printing pipeline is best avoided." I've never heard of this or
seen any evidence of this.





--
Roy Harrington
roy@...
www.harrington.com

Re: Optimal TIF file resolution for QTR?

2017-02-28 by brian_downunda@...

Thanks Roy. It doesn't matter to me or the OP as we're both on Windows. It doesn't matter to me as I think that the resampling done by QTR on Windows is just fine. I did one or two real world image tests comparing QTR resampling with Qimage, and while Qimage is arguably slightly better, it wasn't enough to be worth the trouble IMHO. But I read a number of credible reports, probably in the context of colour printing through the Epson driver, about the poor OS X printer pipleline resampling, such that they made an indelible impression on this poor Windows user. Perhaps QTR @ 720 ppi is less affected.


---In QuadtoneRIP@yahoogroups.com, <roy@...> wrote :

But my real point is that none of this matters.

RE: [QuadtoneRIP] Re: Optimal TIF file resolution for QTR?

2017-02-28 by Dave Trout

Roy,

Thanks for the reply.  So it seems that QTR on Windows will resample in all cases, even when the input file is exactly 720ppi.

 

But I’m now actually more confused.  I like to think I understand how printing software works for the most part, but I don’t understand what “correct pixel boundary” means and how the margins of my image (presumably you mean how much space between the image edge and the edge of available printable space within the page size) affects whether you need to resample or not.

 

Can you elaborate on this?

 

I fully understand your perspective on wanting to de-emphasize “exactness” in producing our fine art, and I respect that.  But like Brian, I think there is enough evidence (and yes, sometimes visible) that resolution-related workflow decisions can impact results.  This is all I’m trying to achieve – informed decisions.  I just want to fully understand my tools so I know how best to use them in producing my desired results.

 

Thanks for all your help and comments.  Dave

 

P.S.  Sorry I won’t be able to visit your show in Los Altos…I’m on the East coast but it would definitely be interesting to see first hand an entire show of QTR-produced work!
Show quoted textHide quoted text
From: QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com] 
Sent: Monday, February 27, 2017 8:05 PM
To: QuadtoneRIP@yahoogroups.com
Subject: Re: [QuadtoneRIP] Re: Optimal TIF file resolution for QTR?

 

  

Dave,

 

I think its more accurate to say in (4) that QTR driver resamples to 720dpi on the correct pixel boundary.

Now, under the best conditions if you set margins appropriately that probably does't change any values.

But if you use metric or you use decimal values in margins you are likely to be doing worse.

Try it out.  Make artificial test cases and see what you get.  You may find it interesting -- but I don't think

it's important in real images.

 

Roy

 

On Mon, Feb 27, 2017 at 2:47 PM, dtrout@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:



Thanks Brian - very helpful.  

I'm a PC user of QTR (should have mentioned that in my original post).  From my reading of the other thread it sounds like QTR will do the resampling on Windows.  I don't want to get into the pros/cons on this topic, I just want to understand exactly what QTR does.  I'll decide what to do with my files from there :-)

So for the cases I mention in the original post, I'm assuming this is the behavior on QTR on Windows:

1.  Input TIF  < 360ppi (QTR will upsample to 720ppi)
2.  Input TIF = 360ppi (QTR will upsample to 720ppi)
3.  360ppi < Input TIF < 720ppi (QTR will upsample to 720ppi)
4.  Input TIF = 720ppi (QTR will NOT resample)

Roy, can you confirm the above?

Many thanks,
Dave 





 

-- 

Roy Harrington
roy@harrington.com
www.harrington.com

Re: [QuadtoneRIP] Re: Optimal TIF file resolution for QTR?

2017-02-28 by Paul Roark

I would think the dithering algorithms might make all this theory about resampling effects rather moot.

In actual practice, it appears to me that the recent Photoshop resizing systems incorporate some type of sharpening if you have the resampling mode in the "automatic" setting. Then again, I find that at least my Sony cameras appear to do some processing even of the raw files that has the effect of (over) sharpening at some edges.

I guess where I'm going with this is that every stage we go through has an impact on the image that introduces artifacts that may be hard to control. In practice and relative to the entire process, those introduced by resampling at the printing stage by the driver seem to be rather inconsequential.

Paul
www.PaulRoark.com

Re: [QuadtoneRIP] Re: Optimal TIF file resolution for QTR?

2017-02-28 by Roy Harrington



On Tue, Feb 28, 2017 at 6:51 AM, 'Dave Trout' dtrout@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:


Roy,

Thanks for the reply. So it seems that QTR on Windows will resample in all cases, even when the input file is exactly 720ppi.

But I’m now actually more confused. I like to think I understand how printing software works for the most part, but I don’t understand what “correct pixel boundary” means and how the margins of my image (presumably you mean how much space between the image edge and the edge of available printable space within the page size) affects whether you need to resample or not.

Can you elaborate on this?


I'm not sure of all the windows libraries, but lots of code these days uses floating point numbers for coordinates,
sizes, units etc. As a programmer, depending on exact floating point values is a bad idea because anything with
a decimal point is not exact (most anyway). No doubt, YMMV.

Roy

I fully understand your perspective on wanting to de-emphasize “exactness” in producing our fine art, and I respect that. But like Brian, I think there is enough evidence (and yes, sometimes visible) that resolution-related workflow decisions can impact results. This is all I’m trying to achieve – informed decisions. I just want to fully understand my tools so I know how best to use them in producing my desired results.

Thanks for all your help and comments. Dave

P.S. Sorry I won’t be able to visit your show in Los Altos…I’m on the East coast but it would definitely be interesting to see first hand an entire show of QTR-produced work!

From: QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com]
Sent: Monday, February 27, 2017 8:05 PM
To: QuadtoneRIP@yahoogroups.com
Subject: Re: [QuadtoneRIP] Re: Optimal TIF file resolution for QTR?

Dave,

I think its more accurate to say in (4) that QTR driver resamples to 720dpi on the correct pixel boundary.

Now, under the best conditions if you set margins appropriately that probably does't change any values.

But if you use metric or you use decimal values in margins you are likely to be doing worse.

Try it out. Make artificial test cases and see what you get. You may find it interesting -- but I don't think

it's important in real images.

Roy

On Mon, Feb 27, 2017 at 2:47 PM, dtrout@...t [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:



Thanks Brian - very helpful.

I'm a PC user of QTR (should have mentioned that in my original post). From my reading of the other thread it sounds like QTR will do the resampling on Windows. I don't want to get into the pros/cons on this topic, I just want to understand exactly what QTR does. I'll decide what to do with my files from there :-)

So for the cases I mention in the original post, I'm assuming this is the behavior on QTR on Windows:

1. Input TIF < 360ppi (QTR will upsample to 720ppi)
2. Input TIF = 360ppi (QTR will upsample to 720ppi)
3. 360ppi < Input TIF < 720ppi (QTR will upsample to 720ppi)
4. Input TIF = 720ppi (QTR will NOT resample)

Roy, can you confirm the above?

Many thanks,
Dave



--






--
Roy Harrington
roy@...
www.harrington.com

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