Perceptual Color versus Relative Color Settings

We are constantly faced with the choice for printing photographs of using either Perceptual color or Relative color.  If you print mostly black and white, like I do, then you easily forget which setting does what.  Paper, ink and time are too expensive to waste, so I have put some references here to resources I use in helping me make that choice.

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Don't forget to visit my photography web site where we sell museum quality black and white prints framed to last up to 175 years - Outdoor Images Fine Art.

DPI and PPI: Which is What?

I come across questions and forums where people use DPI and PPI interchangably. Unfortunately, I am also guilty. I have found what I thought was a great explanation of the difference. I have copied the article here and provided a link to the original.

DPI and PPI Explained

There seems to be a great deal of confusion among many people regarding the use of some terms in digital imaging. The main problem with this is that DPI (dots per inch) is an old term that has been applied to everything relating to resolution and the size of a digital image. This is very confusing because different situations work with resolution in very different ways, and having a single term for all of them just makes things more confusing. More recently, the term PPI (pixels per inch) has appeared in common usage and is far more specific for what the term entails. DPI is still used in some documents and software when PPI is really what they mean, but this is changing. This article is an attempt to explain what the 2 terms mean and how they should be used.

As usual, this article originally saw light in a Usenet group. In this case, rec.photo.digital. The article is a combination of 2 seperate posts I made regarding the difference between DPI and PPI, with some additional editing.

PPI

Okay, let's start with PPI, it's easy to understand. This is the number of pixels per inch in your image. This will affect the print size of your photo and will affect the quality of the output. The way that it will affect the quality of the output is that if there are too few pixels per inch, then the pixels will be very large and you will get a very pixelated image (jagged edges, you will actually see individual pixels, not good). You'll hear various different numbers thrown around as to what an acceptable PPI for a print-out is. A lot of this will depend on the size of the print. This is because you look at large prints from a further distance than a small print, so you can get away with a lower PPI and still have the image look fine.

Anyways, all that PPI does is affect the print size of the image. There are 2 ways that you can change the print size, by resampling or by not resampling. Not resampling is what you normally want to do, this will only change the size of the print out. Using resampling will actually change the number of pixels (and thus the file size) in order to match the print size. So for instance, if you don't resample, changing the PPI setting will increase or decrease the print size (it will increase if you drop the PPI, it will decrease if you increase the PPI). With resampling, if you change the PPI, you will loose pixels (if you set the PPI to a lower value) or you will have pixels created (if you increase the PPI). Creating pixels is a bad idea, they get generated by the computer and the results aren't usually that good. Throwing away pixels is fine as long as you won't need the bigger size later (that's why it's usually a good idea to save the original large file).
An Example

Suppose you have a 100 x 100 pixel image could be printed at many different sizes. If you set the image to print at 10 PPI, then you'd have a 10" x 10" image. If you set the image to print at 100 PPI, you'd have a 1" x 1" image. Note that adjusting this value doesn't effect the number of pixels in the image at all, it just changes how big the print will be.

Take our 100 x 100 pixel image again. Suppose it's set at 100 PPI (producing the same 1" x 1" printed image). With re-sampling off, when you adjust the PPI the dimensions adjust as well, this is how things worked in the example above. With re-sampling on, the dimensions won't change. So, if you changed the PPI to 10 with re-sampling on, you would still keep a 1" x 1" image and the computer would throw out pixels to make the image stay that size. So in this case, you'd end up with a 10 x 10 pixel image in the end. If you went the other way, and changed the PPI to 300, then the computer would generate pixels to make a 300 x 300 pixel image that's still 1" x 1" when printed.

Usually, the only reason you want to use re-sampling is for reducing the size of your image. For example, my scanner produces 3888 x 2592 images. These images are too big to use online (both for display and because of filesize). By using re-sampling, I can adjust the size of the images to something more appropriate for online use.

DPI

Now let's talk about DPI. DPI only refers to the printer. Every pixel output is made up of different coloured inks (usually 4 or 6 colours, depending on your printer). Because of the small number of colours, the printer needs to be able to mix these inks to make up all the colours of the image. So each pixel of the image is created by a series of tiny dots (you could think of them as sub-pixels). Generally, the higher the DPI, the better the tonality of the image, colours should look better and blends between colours should be smoother. You'll also use more ink and the print job will be slower. You might want to try setting your printer to a lower DPI to save ink and speed up the job, see if you notice any difference in quality. The lowest setting where you don't see any loss in quality should be the best one to use.

So a 1200 dpi printer uses 1200 dots of ink in every inch to make up the colours. If you were printing a 300 PPI image, then every pixel would be made up of 16 smaller ink dots (1200 DPI x 1200 DPI / 300 PPI x 300 PPI). A lower DPI would have fewer ink dots making up each pixel, which would make the colour look worse. A higher DPI would have more ink dots for each pixel and should give more accurate colour (especially under close examination).

Copyright

frugal@tildefrugal.net
Copyright © Andrew Dacey

See the full article here at: http://www.tildefrugal.net/photo/dpi.php ... Read More!

Don't forget to visit my photography web site where we sell museum quality black and white prints framed to last up to 175 years - Outdoor Images Fine Art.

Creating a Custom Contact Sheet in Lightroom

Creating a custom contact sheet like this one is easy to do in Adobe Lightroom. This type of contact sheet is especially important when using our film scanning workflows. We use this contact sheet to easily see what negatives are stored in specific binders allowing easy location of the originals. Here we will show you the steps to create your own contact sheet.

Where to Start

Begin by selecting some images. We use images by selecting a specific file folder where we store our images by either roll of film or roll of slides. See my article on Digital Management of Negatives and Slides.

After selecting some images, move to the print module. There select the lightroom template you wish to start with. We chose the 4x5 Contact Sheet. From there it is all customization.

Customizing the Contact Sheet

First we will set a title for our work. We need to allow room for a title to show, so we set the top margin in the layout tab to 0.75 inches. You can use any size that fits your needs. Then we set an identity plate that includes, most importantly, the file folder for the images. Remember from our workflow that the folder name is the identification for the series of images. In this case, the folder name is 2008-D-1. You can also use a description for the photo shoot if you like.

To change the identity plate, first select the checkbox for the identity plate under the overlays tab. Then click on the little down arrow at the bottom of the plate sample and select the Edit menu. Select the text identity plate option if necessary and type the description. Simply press the ok button without saving the identity plate, because it will change each time.

Next, select the Override Color checkbox and select a black color for the title. Be sure that the Render behind image and Render on every image checkboxes are turned off. Now you will see the identity plate in the middle of your contact sheet. Using the mouse, drag it to the top of the page. By setting your top margin, you should have ample space to show the title.

We also need to add a page number in case there are more images than will fit on a single page. Select the Page Numbers check box under the Page Options after the indentity plate. You should see the number one in the bottom right corner.

The only customization remaining is the text to show under each image. Check the Photo Info box and select the drop down Edit menu item. Here we will add the standard information we would like to see next to each image on the contact sheet.

This should bring up a dialog box similar to the one below. We will enter the filename and other information for each image. Note that you can choose whatever information you like, but you should choose the filename first if you will use the contact sheet as part of your archiving and storage workflow. This will help identify frame numbers and filenames later on.
By selecting information that you wish to show and pressing the insert button, the lightroom codes are input to the top and a sample filename is shown. Notice we use the Filename first and then any exposure information linked to the image. If the image is digital, then the exposure information exists. If you are scanning slides or negatives, this information probably doesn't exist and the filename is sufficient. Notice how we have added labels such as 'exposure' in the template area to describe the information added.

Be sure to press the drop down at the top of the dialog and select the 'Save current settings as New Preset' item. Then name it something meaningful like '4x5 contact sheet info'. Press Done and see what your preview looks like. It should be similar to the one presented at the top here.

Saving the Preset

Almost finished! Let's save what we have so far by adding a template. Press the Add button on the bottom of the left panel and enter a name similar to the one shown here. After you are finished, you can tweak the settings, right-click on the template name and select the 'Update with Current Settings' menu item.

Conclusion

Working with digital images from RAW sources or from negatives and slides still necessitates the printing of contact sheets. Set your up like this and easily add it to your work flow. ... Read More!

Don't forget to visit my photography web site where we sell museum quality black and white prints framed to last up to 175 years - Outdoor Images Fine Art.

Identity Plate Known Bug in Lightroom 1.4

Adobe indicated that there is a known bug in Lightroom version 1.4 that affects the Identity Plate overlays in the printing module. We reproduce that bug below to show you how to fix it.

In the print module the Overlays section looks like the image to the left. Notice you can check the Indentity Plate box and the Render on every image box. This will cause the text or graphic to show on every picture selected to print. This is true for contact sheets and other forms of printing.

Now try to deselect ONLY the Identity Plate checkbox. Notice in the image below how the Render on every image checkbox is greyed out, but still checked. Also notice the identity plate is still visible in the image.


If you reselect the Identity Plate check box, deselect the Render on every image checkbox and then finally deselect the Indentity Plate checkbox again, you will end up with what is shown below. Notice the identity plate is no longer shown in the image.


Remember this is a known bug and Adobe should fix it in a future release. The good news is we know about it and we can fix it on our own. ... Read More!

Don't forget to visit my photography web site where we sell museum quality black and white prints framed to last up to 175 years - Outdoor Images Fine Art.

Printing in Lightroom using ICM with an Epson R2400

When you discuss printing in Adobe Lightroom you are liable to be met with a frown and an immediate discussion of how it doesn't work the way it should. There are many articles on the web and in publications that deal with printing. These articles give you step by step instructions with Lightroom and generic printers. Sometimes they even give you information on setting Epson printers.

After spending about four hours very late last night attempting to research the proper settings and match paper and ink to the screen, I have found the magic recipe for my printer. Thus, we will discuss the settings for the Epson R2400 to print in Adobe Lightroom using ICM. First, we will discuss the settings so that you can begin to print. Then, while your printer is working through the image, you can read about the research I did. Note that we will discuss black and white settings in another article as I have found those settings much more intuitive and easy to create.

First Things First - Prerequisites for ICM Printing

ICM stands for Image Color Management and uses what are known as ICC profiles. These are calibration profiles developed using standards from the International Color Consortium. For more information on these topics, follow the links provided.

In addition, your monitor must be calibrated. I use the i1Display2 by X-Rite also found as Gretag Macbeth Eye-One color management. The i1Display2 costs about $250US and will calibrate your monitor only - CRT, LCD and Laptop. There are many web sites where you can send a printout from your printer and have them create an ICC profile for you that I cannot justify more money for printing calibration hardware. This product is the best bang for your money.

You must also have ICC profiles for your printer and paper combination. Epson R2400 ICC profiles can be found on Epson's web site. Download these files and run them to extract the profiles to the proper place on your hard drive. Be sure to download the windows or macintosh versions appropriately.

Finally, your preparation includes being sure you have the most current printer driver. This is important to get new updates and my experience has been this is not done automatically. I purchased an Epson R2400 new in November of 2007. I used the CD included to install the driver. I have yet to receive a notice in windows indicating I have an update ready and I have not been successful determining the version of the software through any of the Epson control panels. That being said, I downloaded and installed the update from the web site and sure enough, it was a new version. The current driver for the Epson R2400 is also on their web site. Be sure once again to choose the appropriate operating system for your computer.

This completes our preparation. Open Lightroom and select an image for printing.

Lightroom Settings for Printing using ICM

Lightroom has a relatively simple interface for printing. Setting up the margins and print space in Lightroom goes beyond the scope of this article. We are dealing with only the printer settings. After setting the layout for an image, go to the bottom of the panel and view the Print Job Settings. Here is where we will tell Lightroom how to handle the color management for our image. Note that none of these selections alter what is viewed on the screen.

In order to print, we first set the Lightroom color management to Managed by Printer. This is a requirement. We will still use the ICC profiles, but we will select them through the printer setup.

Epson R2400 Printer Driver Settings

Next, press the Print Settings button to bring up the printer dialog. Press the Properties button to access the printer settings. In this example we are using 13x19 Velvet Fine Art paper. Set the paper type as shown in the image to the right.

Next, press the Advanced button if you are not already in the advanced mode.


These settings are extremely important. I have not found a reference to these settings in any print book or on the web. I think they are uniquely presented here.

When you open these settings, most of them are already set by default. If not already selected, select ICM color management. The mode should already be set to Driver ICM (Basic) as shown. In addition the intent should be set to Perceptual and the printer profile should be Epson Standard. Ignore the printer profile description for now as you cannot change it anyway.

Now select the check box for Show all profiles. This will enable all profiles on the computer to be available for selection. Use the drop down box under input profile and find ProPhoto RGB. This is the key to printing in Lightroom with the R2400.

Lightroom already uses this color space and although I have not been able to confirm it, if Lightroom is not managing the colors, it stands to reason that the ProPhoto RGB space is sent to the printer driver without manipulation. The results of my prints seem to confirm this is true.

After changing the input profile, the profile description at the bottom should match the ICC profile for the paper you have selected. In this case, our example shows the Velvet Fine Art paper correctly.

Using Print Preview in the Printer Driver Settings

While not required, I am trying to determine how accurate the Epson preview pane is. Thus, I have selected the checkbox for Print Preview. Many sources on the web have said not to trust this preview. However, it appears that the preview will tell you if what is being sent from Lightroom is close to what was on your calibrated (hopefully) monitor. It also appears through trial and error, that the preview will also show the modifications made by Lightroom if you chose to let Lightroom handle the color management. Thus, for now I trust it to show if I am in the right ballpark.

Saving the Preset Configuration in Lightroom

After making these changes, press the OK button on the printer driver dialog and then again on the printer settings dialog to return to Lightroom. Before doing anything else, save your settings as a preset. I have organized mine by paper type, then size of the print and then whether the print is matted or not. You can easily create folders, save a preset and drag it to your customized folder. These presets save the printer settings so they are important. Creating these settings is beyond the scope of this article and will be covered in a later article.

Press Print

We are now ready to press print! If you have made these changes, your print should come out very close to what is on your screen. This is provided of course you have setup your system and calibrated it correctly. I strongly recommend using the printer preview in the R2400 driver until you feel confident you have your settings correctly. While it may not be a perfect translation, the preview will tell you if you are way off the mark.

Research on Printing in Lightroom

After printing several prints using various settings where Lightroom whereby Lightroom controlled the color management, I gave up. The prints either had such bright saturation that Velvia film looked dark and pale, or the prints contained strong magenta hues. Yes, I had the printer set to ICM and No Color Management. I believe it has to do with the wide gamut of the ProPhotoRGB color space and mapping to the printer driver through Lightroom.

The method I presented above uses the default Lightroom color space and allows the Epson driver to manipulate it. This process has provided very acceptable results to me using the various Epson Fine Art papers. I have not experimented yet with the Luster paper and other vendor's papers, partly because I try not to switch often between matte and photo black cartridges due to ink waste.

Here are some of the sources I used to arrive at these conclusions:

• O'Reilly had this article on their Inside Lightroom site
• Killer Tips has this printing video
• Photo.net has this forum article
• Open Source Photo had this exchange on their forum
• Adobe uses this link to various printing articles for Lightroom
• Digital Photography Review had this thread on their forum

If you review these many say to let Lightroom manage the color. A few forums suggest we should let Epson manage the color. However, no one suggests that we set the input profile to the same one as Lightroom uses.

Let me know your experiences. ... Read More!

Don't forget to visit my photography web site where we sell museum quality black and white prints framed to last up to 175 years - Outdoor Images Fine Art.

Lightroom Presets

Lightroom makes especially functional use of presets and templates (for web galleries). Photoshop allows a user to add preset tools in a list, but the presets are of all types and to find one a user has to scroll throughout the list looking for the correct tool.

Lightroom has various sections where presets can be stored and used, but each is unique to the module being worked in. For example, you can store templates or presets for meta data to attach to newly imported images. I use this template for my copyright and ownership information - i.e., information that should appear in every image no matter what.

There are also presets that can be saved for items such as custom cropping aspects. I use 11x14, 13x19 and 11x17 here.

Printing, slideshows and web layouts all have user definable presets or templates available. This makes repeat work in these areas a snap. The printing area I use the most and it is finally nice to have a way to set printing properties without having to reset the printer each time. ... Read More!

Don't forget to visit my photography web site where we sell museum quality black and white prints framed to last up to 175 years - Outdoor Images Fine Art.