Monthly Archives: June 2012

Could the Nikon D800E be the answer for Gigapixel Panoramic Photography

Could the Nikon D800E be the answer for Gigapixel Panoramic Photography?

When it comes to panoramic photography, it’s hard to argue with the concept that bigger is better.

Bigger prints have more of a wow factor and for bigger prints you need bigger images which have the added advantage of having better detail.

Thanks to a new breed of panoramic heads like the Gigapan Epic series, panoramic images are now measuring in the gigapixel range but there is a problem….

Ever wondered why so many of the ultra large images are shot in bright sunlight or flat lighting conditions? This question becomes more pertinent when you consider that sunrise and sunset is often the best time to shoot panoramas with mood and ambience…

The answer is very simple; Gigapixel images need to be shot in lots of segments. Lots of segments take a lot of time to shoot. Lots of time is something you don’t have at sunrise and sunset with fast changing lighting conditions.

The solution, use higher resolutions cameras…

By using a higher resolution camera, you increase the pixel count of each frame meaning that you need to shoot less frames.

That was an easy solution to the problem or did the solution possibly just create a new problem.

Often the best panoramic images are shot in places that are the hardest to get to, like from the top of mountains or along hiking trails. Adding a robotic head to the equation has already upped the weight of your panoramic kit considerable and adding a high res medium format camera to the equation may just literally tip the scales and leave you with kit that is too heavy to carry.

And just in time a very unlikely saviour enters the equation in the form of the Nikon D800E.

With an extreme 36mp low noise sensor, sensor capable of producing ultra-sharp images and a body that weighs less than a D700, the D800E could just be the large format panoramic photographer’s saviour.

Ok so the images it produces are not quite double the D700’s size being 7,360 x 4,912 opposed to 4,256 x 2,832 in fact it’s 1.7 times bigger but that’s quite a bit when you consider the following.

Let’s say that we are shoot a panorama that’s 12 images wide and 4 deep using a 50mm lens and a 12mp camera. Ok that’s 48 segments and if we are shooting 7 frame HDR at sunset and each bracket set takes 1 minutes that’s 48 minutes to complete the image. That’s a little bit too long for that time of day and you are most probably going to hit some serious issues with changing light.

Now if we were using the D800E with 36mp we would be able to use a 30mm lens and only need to shoot 28 segments meaning that the image would take 28 minutes to shoot and the final panorama would still have the same size in pixels. That’s a huge improvement time wise even though it’s still probably a little bit too long. We would probably be aiming for something like 16 minutes but the D800 handles noise so well, we might as well just crank it up to 400 iso (wouldn’t take any camera higher unless I really had to) and we will come down to something that is manageable.

Also at 28 images and a 30mm lens we could still get away with a manual head so once again we have lightened the load.

I shoot with both a 360prescision Giga manual head and a Gigapan Epic Pro Robotic head and watch this space because the D800E is on my wish list for the very reasons I have mentioned above.

In case you are wondering why the D800E and not the straight D800 well the answer is simple, the lack of AA filter in the E makes it significantly sharper than the normal model. Yes you run the risk of moiré but photographers have been removing the AA filters from their D700’s and D3’s for a while now and the cases where moiré becomes a serious, irreparable problem are so few that it’s well worth going this route for panoramic photography.

 

 

Understanding Colour Management and Printing

In the last few days I have heard photographers mention adjusting their screens to match a particular printer’s images and I thought it was time to revisit this topic.

Let’s pre-empt this article by saying the following. Everything in a colour managed workflow needs to be adjusted but no item in the workflow is ever adjusted to match any other item!

Ok let me explain…

In 1993, the International Color Consortium was established by eight companies involved in the colour printing industry. The reason for the creation of the ICC, to quote their website was as follows:

The International Color Consortium was established in 1993 by eight industry vendors for the purpose of creating, promoting and encouraging the standardization and evolution of an open, vendor-neutral, cross-platform color management system architecture and components. The outcome of this co-operation was the development of the ICC profile specification. (www.color.org)

Basically what this means is that there needed to a universal non-proprietary standard against which all colour was measured and this has become the ICC profile specification.

Today colour management across devices such as printers, screens etc. is a achieved by profiling the devices to that they conform to the ICC profile specification and reproduce colour accurately as defined by this standard.

This means that printers are profiled using ICC profiles and screens are profiled using ICC profiles and both are profiled to the standard, not to each other.

Before we start there is a very important concept we need to understand and that is Colour Gamut. Every device has a colour gamut and in our case, Wikipedia defines it as “the subset of colors which can be accurately represented in a given circumstance, such as within a given colour space or by a certain output device.

Basically the range of colours that a particular device can accurately reproduce. Colours that fall within a devices gamut range are referred to as in gamut colours and colours that fall outside are referred to as out of gamut colours. ICC profiles don’t only ensure the accuracy of in gamut colours abut they also help the devices deal with out of gamut colours by mapping them to the closest in gamut colour.

 

Step One – Capturing accurate Colour

The first step in the chain applies to anyone producing content that will be printed and in our case it’s us photographers. Absolute colour control starts earlier than many of us realise because it begins with our cameras. Shock, horror, dismay… Yes none of our cameras actually produce an accurate reproduction of what they are photographing. For most of us this isn’t a problem but for those doing colour critical reproduction, it’s a huge problem.

So this is the first time we encounter ICC profiling and to profile our cameras we use something like the X-rite colorchecker passport system.

What happens is that a special colour accurate target, with known colour values, gets photographed and the raw file is read by the Colorchecker passport software.

The software analyse how the camera sees colour and creates an ICC profile that tells applications, like Adobe Camera Raw, how to correct the cameras output so that it’s accurate.

Ok for some of us step one is now taken care of and for others step one isn’t necessary so on to step 2.

 

Two – Viewing accurate Colour

Now that you have a file that contains colour data, correct or not, you more than likely want to view it and edit it on screen. To do this we need to ensure that the screen we are using displays colour accurately and this is the first minefield in the workflow. Trying to get accurate colour from display devices is very difficult and you need to accept the following:

  • Very few displays are even remotely accurate out of the box, apple included
  • Most displays cannot be 100% accurately profiled
  • You pretty much get what you pay for so that cheap screen you got may end up costing you in the long run.
  • Glossy screens are bad news. They can still be profiled but the glossy layer fools your eye by giving the impression of added contrast and vibrancy.
  • Calibrating your screen with your eye will not in any way ensure its colour accurate.

To calibrate a screen you need special software that tells a screen to display a series of known and ten reads what the screen actually displays with something like the Colormunki Display. There are various devices on the market but the Colour Munki is my preferred option for the photographic industry. For colour critical applications I would probably recommend X-rite’s I1 range.

 

As was the case with the camera, the information displayed by the screen is analysed and an ICC profile is created to correct the colours the screen displays and to map out of gamut colours.

The problem with screens is that the gamut can vary greatly depending on the quality of the screen, the age of the screen and screens also drift over time so they need to be profiled regularly. The quality issue means that most screens will only be relatively accurate so colour critical work should only be performed on screens certified for colour accuracy.

Right step two done and we are way ahead of the pack because we now have a pretty good idea of what our images look like and how they should print. Going forward from here we do not adjust our screen to try match anything else. If we find our screens are slightly out, we need to rather adjust what we see knowing that our screen has limitations.

Now we move onto the real problem area…

 

Step Three – Printing Images

Ok this is pretty much where the wheels come off…

Like everything leading up to this, pretty much very printer needs a unique ICC profile for every single paper it prints on. I say pretty much because the HP Z series are a very unique exception which we will cover later.

The reason that the wheels fall off at this stage is that printer colour management can be a very tricky and time consuming and achieving accurate colour output is well beyond the average printer owner.

Let’s first deal with inkjets as these are now the most common form of photographic printer on the market. We aren’t even going to bother with laser printers as they are generally not good enough for photographic reproduction.

The first fact we need to accept is that no two inkjets are identical. Even the same models from the same manufacturer will be subtly different from device to device.

Professional and prosumer printers generally ship with a predefined set of media and ICC profiles but there are two problems with this that mean you will only get relatively accurately colour.

  • As we mentioned every individual printer prints slightly differently.
  • Every batch of media is slightly different.

Using the canned media setting and ICC profiles will suffice for most printing but and this is a big but…

You can only use a media setting and ICC profile for the exact media and printer model it was created for.  Selecting Jimmy’s super white media settings and ICC profile to print on Frank’s bright white paper will not work. Every paper has different characteristics and coating and the ink for the printer will react differently with each paper giving a different result.

Sadly many people offering a printing service don’t know this and quite happily interchange settings and media.

For accurate, consistent colour reproduction ideally every single batch of paper needs to be profiled on the printer it’s being used on but seeing this is expensive and can be difficult most printer just choose the profile they think is closest.

This is why so many people find that prints from the same file differ from print shop to print shop.

So why not just adjust your screen to match the print from a print shop?

Well firstly you will have no idea of what your image actually looks like and secondly you will not be able to reproduce the image across different types of printing with any manner of accuracy. Also this effectively ties you into a single print shop… If you know your screen is reasonably accurate and your print shop’s prints are not close, ditch the print shop don’t touch your screen.

Most high end printer manufacturers now offer a profiling system to make sure that print shops can get accurate colour however in most cases this is an optional extra and is quite costly.

X-rite and other companies once again have stand-alone solutions to this problem. In the photographic range X-rite have the Colormunki Design and Photo which are simple to use and do a good job of profiling printers. This ensures relatively accurate colour but once again the I1 and X-rite pro range is available for those wanting professional colour management.

 

This brings us to the HP Z series that I mentioned earlier.

A few years ago HP made a decision that shook the printing industry. They decided that colour management would no longer be an add-on where their pro printers were concerned but rather that it would become an integral part of the printer design.

At the same time they launched a new range of devices were part of a system called Dreamcolor. Dreamcolour was designed by HP in conjunction with DreamWorks Animation SKG and began when they worked together in 2001 on the animated feature “Shrek”. Because Dream works needed accurately reproducible colour across a range of devices HP designed a profiling system to work with a range of their Dreamcolor certified devices and also develop the mind blowing 32bit Dreamcolor monitor as part of the project.

The Z series which was the projects flagship printer took a radical step forward by including an I1 spectrophotometer as a built-in integral component of the printer. No longer would HP printers rely on colour management being an option, from here on it was mandatory.

HP also took the whole process one step further by using what was essentially a double ICC profiling solution. They realised that by having a profile in the printer that could cater for discrepancies between batches of media and individual printers, you only ever needed to create a single ICC profile for use when printing.

The way it works with the Z series printer is that you first have to do a media calibration. This is a quick automated task that makes sure the print output conforms to a basic standard. Next you create an ICC profile for media based on a printer conforming to the basic standard for that media. You cannot create the ICC profile unless the printer has been calibrated and by doing this HP ensured for the first time that canned ICC profiles would produce highly accurate results. At the same time they took the complex task of colour management and reduced it to a few easy clicks of a mouse.

But they didn’t stop there…

Up till the introduction of the Z series, most inkjets used a derivative of the Cyan, Yellow, Magenta, and black printing system.  The problem with the CMYK colour space is that it has a relatively small gamut and battles to reproduce colours that fall in the bright green, intense orange and royal blue to violet spectrum. HP and surprisingly Canon took a bold step, coincidentally at the same time, by introducing a Red, Blue and Green ink into the equation and both companies led through their teeth about what they had done.

Years ago Pantone developed a system called Hexachrome to get around the limitation of CMYK. Essentially they added two extra colours to the equation namely a bright orange and green to address the limitations that CMYK had in these areas.

Something went badly wrong with Hp’s implementation of this new set of colorants. I like to call this the strawberry saga as it was a strawberry that first highlighted this issue.

For some reason the Z3100 (the first HP printer to include these inks) battle to produce dark saturated reds, a colour that a device that was still primarily CMYK based should not have had a problem with.

Ironically it was I and another South African Z3100 owner along with only a few international sites who discovered the problem. I did a lot of testing which eventually culminated in HP sending engineers to SA to evaluate my findings.

Firstly what I discovered is that HP didn’t have a red ink, they had a bright orange, a bright green and a violet blue ink. Hang on a second that’s not RGB, it’s simply Hexachrome with an additional violet ink.

Testing also revealed that the problem was worse when using the internal profiling system as opposed to an external solution and my suspicion and its one that I still maintain today is that the issue was a combination of HP’s ink mixing tables and the internal profiling system not being able to deal properly with a hexachrome derivative system.

HP never confirmed or denied what went wrong or fixed the Z3100 for that matter but they released the Z3200 which I tested prior to release and which shipped without the red issues. Profiling the Z3100 with an external system has to an extent alleviated the problem in all but a few cases but it is no match for the Z3200 which succeeded it.

Another interesting development was that some well-known and trusted imaging sites that gave the Z3100 rave review prior to its launch were left with eggs on their faces. One or two of them did openly disclose that they may not have tested the machine thoroughly or with images that revealed the problem but others were adamant that the problem did not exist and as a result lost a lot of credibility.

Currently all the leading manufacturers have a Hexachrome derivative printer and all of them are trying to use misleading jargon to make them sound more glamorous than they are.

At the end of the day none of them are HDR, RGB or a host of other misused marketing terms, they are simply Heptachrome printers and while they have extended gamut’s, they still need to be ICC profiled properly before they produce colour accurate results.

I know this is about colour but while we are here we might as well cover some more confusing jargon and explain some ink technology.

Firstly let’s look at the word Giclée or rather what a Giclée print in fact is. I get people often telling me that they aren’t sure about my prints because another printer told them mine are inkjet not Giclée.

I am just going to quote Wikipedia verbatim here:

The word “giclée” was created by Jack Duganne, a print maker working at Nash Editions. He wanted a name for the new type of prints they were producing on the IRIS printer, a large format high resolution industrial prepress proofing ink-jet printer they had adapted for fine art printing. He was specifically looking for a word that would not have the negative connotations of “ink-jet” or “computer generated”. To make the word descriptive of ink-jet technologies he based it on the French language word “le gicleur” meaning “nozzle”, or more specifically “gicler” meaning “to squirt, spurt, or spray.

So we all happy that Giclée is just a fancy word for an ink-jet print?

Next let’s look at Archival

Archival print is a very vague term that is often thrown around to confuse consumers, in reality all prints will eventually fade. How long that print will take to fade depends on the way the print is stored, the paper it’s printed on and the ink that is used. Generally Archival means the print should last more than 10 years without any fading when displayed normally.

How long exactly this should be is a matter of debate. Some say 30 years, some say 100 but what is interesting to note is that even original paintings change over time and in some cases; ink-jet prints are out living the original artworks that they are copies of.

Some of the top end inkjets have ink-jets that are rated at more than 100 years in accelerated tests but in most cases this would not apply to prints that would be displayed in a normal frame and exposed to direct sunlight for extended periods of time.

Most of the testing on the longevity of prints has been conducted by Wilhelm image Research http://www.wilhelm-research.com.

They have published a free book outlining print care and how prints should be stored which can be found here http://www.wilhelm-research.com/book_toc.html for anyone who is interested.

The two main factors that we are worried about are paper and ink.

 

Paper

Paper used to play a larger role on ink fading in the past but newer inks are far more fade resistant so that biggest problem with paper is yellowing and disintegration. What we ideally look for in paper is three things:

  • A paper that is acid free or has a very low acid content. Cellulose papers can fall into this category but the active acid pulp must be eliminated. Acid in paper is a major component in destroying prints. Cotton Rag is often preferred for fine art prints because it isn’t made from wood pulp and doesn’t have the acid problem that needs to be dealt with. The twoi main types of paper are:
    • Conservation-grade — acid-free, buffered paper made from wood-based pulp.
    • Archival-grade (also Museum-grade) — cotton rag paper made from cotton pulp.

Recently recycled plastic has also been used to make Archival grade paper.

  • No or limited optical brighteners. Optical brighteners make everything nice and white but over time they tend to fade resulting in the paper going dull or yellow. Most good long life inkjet paper have no or limited quantities of these.
  • Unbleached paper. Paper is sometime bleached to make it whiter as opposed to just using optical brighteners but sometimes the two techniques are combined. Bleaching is not environmentally friendly and there are also concerns about the longevity of bleached paper.

 

Ink

Now onto the most confusing of the two being ink.

Essentially there are three main types of ink- inks namely: Dye, Solvent and Pigment.

 

  • Dye inks have the advantage of being the moist vibrant but traditionally they have been water based and fade quite quickly.
  • Pure Pigment Inks consist of micro pigment particles, They have by far the longest life span but have been fingered as the culprit behind head clogging when the pigment clumps or falls out of suspension. The HP Z series have an ingenious ink agitation system that all but eliminates this and results in very few head clogs and substantially less head cleaning.
  • Solvent Inks. Traditionally solvent inks have been used for outdoor and signage applications. Theses inks can last up to 4 years in direct sunlight which has led some people to mistakenly believe that they should be able to last way beyond this indoors and are marketing their solvent prints as Archival. In most cases the ink itself starts to degenerate after 4 years and these prints can fade very rapidly thereafter.  Most manufacturers of these machines warn against using these inks for Archival printing.

Epson has recently developed an Eco solvent ink that does last over 100 years but HP’s Vivera pigment inks still rule the roost with the longest life span tested to date.

HP also has a new latex based ink technology but I have not seen the longevity tests on this yet.

 

Photographic Printers

Another class of printers is a photographic printer these work by exposing a piece of photographic paper with a laser or lasers. Examples of this type of printer would be the Fuji Frontier, the Light Jet or the Lambda.

Many purists still love the technology because it’s still a photographic process where the exposed paper needs to be processed with chemicals however also many of them believe or have been misled to believe that these prints will outlast modern ink-jet prints. In fact the opposite is true with some modern inkjets being tested at double or in the case of the HP Z series, even triple the longevity.

Additionally inkjet prints can be a lot sharper and more detailed.

Photographic printers like inkjets also need to be profiled with ICC profiles and can produce excellent but in some cases changes in chemistry or paper can affect accuracy and this need to be carefully monitored.

 

Commercial printing

At the far end of the spectrum we have the long run commercial printing e.g. Litho printing. Most of these are wet ink system that rely on a plate based system but once again ICC profiling plays a role here to however this is a very complex situation and I am not going to cover it suffice to say the same general profiling principals apply.

 

Almost Done

Hopefully now you understand a little bit more about the complexities of printing and are more equipped to deal with printers who try pool the wool over your eyes.

Having said this though you will need to have a properly calibrated screen to be able to argue that an image has not be printed correctly. A final check is to get an X-rite colour checker http://xritephoto.com/ph_product_overview.aspx?ID=820 , give the printer the checker in digital format and ask them to print it.

If the printer is properly profiled, you should be able to print out the chart, place it next to the one from X-rite and it should be hard to tell the difference between the two. In the worst case differences should being relatively minor.

If I do this with my HP, I battle to tell which is the print and which is the original.

 

Update:

Seeing I discussed the HP Z series someone asked me what I think of them and would I recommend it. This is a difficult on to answer. The Z series has been extremely successful internationally but in South Africa unfortunately you get HP and its supply chain along with the printer. The z3200 is already 4 years old but it can still compete with or better anything I have seen from any other manufacturer.

In 4 years I have had 2 nozzle clogs and only cleaned the print heads about 6 times which is pretty impressive but HP SA are their own worst enemy.

I was also asked about using refilled or third party inks.

I don’t even need to think about this…

The answer is simply hell no!

Genuine ink may be competing with gold in price but the genuine inks are designed to last and to work with the particulars printers heads. One of the latest test from Wilhelm Imaging Research http://www.wilhelm-research.com/hp/NonGenuine-3rdPartyInkRefills.html says all that needs to be said.