So, I grind, tamp, and install the filter. I push the button, and within a split second, I see light brown water shooting out of the filter…

That’s not what’s supposed to happen. Maybe I did not tamp enough… So, I try again - with the same result. Maybe the setting on my grinder got changed, adjust, grind, tamp, and give it another try - with the same result.

I notice that I can turn the handle of the filter a lot farther than usually… Did something break in the group head?

ARRRRGGGGHHHH… I need my morning coffee! My despair is good news for the local coffee shop.

After breakfast, I try to get on Rancilio’s web site to see if they have any troubleshooting instructions. The web site is down. The Italian web site is down too. Is this a conspiracy to drive me nuts?

OK, I have not cleaned the machine in a while, let’s start with that. Sure enough, the machine needed a good cleaning. I put everything together again, try another shot - the same result.

While disposing of the grounds, I notice something: The grounds are cold. They should be hot, but given the speed with which the water rushed through, at least a bit warm. Cold. Hmmm… I realize that not just the grounds are cold, the filter is cold too… and the group head too, and the whole machine is cold. Even though the “heating” lamp is on, the machine is not heating.

Aha! That explains everything. How could I miss that important clue?

So, let’s try Google. And sure enough, I find information about how to reset the thermal protection “thingy”. I open the machine, look around, and there it is: A small red button. I push it and hear a “click”.

I suppose that means that the thing actually got triggered. After putting the cup warming tray back on I turn the machine on, and after a couple of minutes I can feel how it is getting warm. Bingo!

Desperate times call for desperate measures, so I do not wait the 30 minutes the machine usually needs to warm up, I do part of the “Cheating Ms. Sylvia” process and pull a shot after 15 minutes: It’s delicious!

I would love to sign up, but unfortunately Rochester is not really considered to be a NYC suburb.

The photos that get the most votes will get published in the book, so please go and vote for me

Why do I no longer look for ham in spam? Because it got too overwhelming. Google keeps a month worth of messages in the SPAM folder, anything older than a month gets deleted automatically. Up until yesterday I had 14000 SPAM messages. Today the count dropped to a bit over 8000. This means that about a month ago I received 6000 SPAM emails in about a day - oh man was I looking back to the good old days of only 300 SPAMs a day. The reason for that was that somebody used my my email address and my domain as the “From” address for a ton of SPAM, and a lot of mail servers out there still send out messages that are trying to tell the sender “your message got classified as spam” or “the user you tried to spam does unfortunately no longer exit”… And all these messages ended up in my mailbox.

This was not the first time that happened, and I’m just too tired of going through these messages and trying to find the needle in the spam stack.

And, because of time constraints, I had to “rush” the whole process a bit by shaving off a few minutes of every step. The temperature on that day (it was very hot) may have worked to my advantage because the dough did rise a lot faster.

French bread is best fresh, and I did not want to eat three loafs within an hour of baking them, so I also cut short the baking time a bit - hence the somehow pale look of the finished bread.

That allows me to freeze the loafs and then just pop them into my convection toaster oven for 8 to 10 minutes and have delicious fresh french bread.

I did some research on why and how visitors come to my site. One interesting finding is that a number of people are searching for information about PDF content streams. Here is the list of the 50 most common Google searches that contain the string “content”:

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So, I guess you want to learn more about what PDF content streams are, and how to create them, with an example or two thrown in… I think I can do that.

In a previous post and here, I’ve shown you how to look into a content stream with the tools that Acrobat has on board. The good news here is that with Acrobat 9 Professional (or Pro Extended), you do no longer have to run a preflight first, the option to browse the internal structure of the PDF is available right away.

What does the PDF spec has to say about content streams?

PDF Specification

Section 3.7 in the PDF Specification talks about content streams (and resource objects - the two travel together). Here we read that “Content streams are the primary means for describing the appearance of pages and other graphical elements.” Section 3.7.1 goes into more detail. The name “content stream” does already give away an important piece of information: We are talking about stream objects. The content stream is a stream object that describes how a page will be rendered. If your recollection of what a stream object is is a bit fuzzy, please review section “3.4.6 Object Streams” in the PDF spec again.

When we look at a page object in a PDF document, we will see a number of required entries in the page object dictionary:

• Type
• Parent
• Resources
• MediaBox

Hmmm… This list does not include the Contents entry (which does point to a content stream). Because this entry is optional, a page does not need page content, so an empty page in a PDF document does not necessarily contain a content stream. This makes it very easy to add blank pages to a PDF file.

Back to the spec: The Contents can be either a single stream or an array of streams. It is up to the creating application to decide which way to go. In general, if it’s possible to create the content stream in one operation, it’s probably best to use a single stream object, whereas a page content that contains different parts that are created either at different times, or copied from other objects or locations would suggest an array of content streams.

Contents of a Content Stream

So, what exactly is the content of a content stream? We find this information in the “Operator Summary” (appendix A in the PDF specification). This section lists all operators and a reference to where the operator is introduced in the body of the PDF specification.

I don’t want to discuss every operator (maybe in a future post - let me know if that’s something you want to see), but just fore reference purposes and so that this stuff shows up if somebody googles for one or more of these operators, here is a list:

b,B,b*,B*,BDC,BI,BMC,BT,BX,c,cm,CS,cs,d,d0,d1,Do,DP,EI,EMC,ET,EX,f,F,f*,G,g,gs,h,I,ID,J,j,K,k,l,m,M,MP,n,q,Q,re,RG,rg,rl,s,S,SC,SCN,scn,sh,T*,Tc,Td,TD,Tf,TJ,Tj,TL,Tm,Tr,Ts,Tw,Tz,v,w,W,W*,y,’,”

Go and read up on those operators

Creating Content Streams

So, how do you create a page stream out of nothing? There are two ways: easy (that is relative!) and complicated.

Let’s take a look at the simple method first.

Using a Library or a Framework

The most simple approach to creating a content stream is to let somebody else to do the heavy lifting: If you have a PDF library or a framework that allows you to create PDF content, then you don’t have to mess with the details of what needs to be where in your content stream. Examples for libraries are of course the Adobe PDF Library, or the Acrobat API (take a look at the PDE level of API functions), PDFLib or iText. Just get familiar with the environment and create PDF content streams as complicated as you need them to be - without too much hassle.

Manually Creating Content Streams

OK, before we go any further, allow me a question: Why do you want to do this the hard way? Just stick to the approach mentioned in the last paragraph and be done with it. There really are not many reasons to torture yourself with this stuff, so just get a nice library and enjoy life…

Still here? There are only two things I can tell you at this point: Read the PDF spec, and read it again, and when you try to create your first content stream, make sure you get the stream length right. If you are dedicated to learning how to do this from scratch, there is nothing I can say that will magically make it unnecessary to read (and understand!) the PDF spec. So, get started, and if you have questions, ask them in the comments to this article. Good luck.

Content Streams in PDF Files

So, what does a content stream in a PDF file look like? Here is an example:

13 0 obj
<<
	/Length 66/Filter/FlateDecode
>> stream
[some binary data]

endstream
endobj

This stream is obviously compressed - which is indicated by the “/Filter” option of “/FlatDecode” in the stream dictionary. Let’s take a look at the uncompressed stream:

The first image shows the content stream of a page using the “View content stream with q/Q nesting levels collapsed”, and the second image uses the “View content stream by marked object”. The important difference is that the first image shows just the content stream operators, whereas the second image shows the operator without any parameters, followed by a description. To see the actual operators with parameters, the individual blocks need to be expanded.

Do you have any idea what this PDF page will look like? Here is the PDF document: test.pdf